Import sources from 2011-03-30 iso image

27 files changed, 4661 insertions, 0 deletions

diff --git a/sys/src/cmd/mk/acid b/sys/src/cmd/mk/acid
new file mode 100755
index 000000000..17c101647
--- /dev/null
+++ b/sys/src/cmd/mk/acid
@@ -0,0 +1,664 @@
+sizeof_1_ = 8;
+aggr _1_
+{
+	'D' 0 llength;
+	'D' 4 hlength;
+};
+
+defn
+_1_(addr) {
+	complex _1_ addr;
+	print("	llength	", addr.llength, "\n");
+	print("	hlength	", addr.hlength, "\n");
+};
+
+sizeof_2_ = 8;
+aggr _2_
+{
+	'V' 0 length;
+	{
+	'D' 0 llength;
+	'D' 4 hlength;
+	};
+};
+
+defn
+_2_(addr) {
+	complex _2_ addr;
+	print("	length	", addr.length, "\n");
+	print("_1_ {\n");
+		_1_(addr+0);
+	print("}\n");
+};
+
+UTFmax = 3;
+Runesync = 128;
+Runeself = 128;
+Runeerror = 128;
+sizeofFconv = 24;
+aggr Fconv
+{
+	'X' 0 out;
+	'X' 4 eout;
+	'D' 8 f1;
+	'D' 12 f2;
+	'D' 16 f3;
+	'D' 20 chr;
+};
+
+defn
+Fconv(addr) {
+	complex Fconv addr;
+	print("	out	", addr.out\X, "\n");
+	print("	eout	", addr.eout\X, "\n");
+	print("	f1	", addr.f1, "\n");
+	print("	f2	", addr.f2, "\n");
+	print("	f3	", addr.f3, "\n");
+	print("	chr	", addr.chr, "\n");
+};
+
+sizeofTm = 40;
+aggr Tm
+{
+	'D' 0 sec;
+	'D' 4 min;
+	'D' 8 hour;
+	'D' 12 mday;
+	'D' 16 mon;
+	'D' 20 year;
+	'D' 24 wday;
+	'D' 28 yday;
+	'a' 32 zone;
+	'D' 36 tzoff;
+};
+
+defn
+Tm(addr) {
+	complex Tm addr;
+	print("	sec	", addr.sec, "\n");
+	print("	min	", addr.min, "\n");
+	print("	hour	", addr.hour, "\n");
+	print("	mday	", addr.mday, "\n");
+	print("	mon	", addr.mon, "\n");
+	print("	year	", addr.year, "\n");
+	print("	wday	", addr.wday, "\n");
+	print("	yday	", addr.yday, "\n");
+	print("	zone	", addr.zone, "\n");
+	print("	tzoff	", addr.tzoff, "\n");
+};
+
+PNPROC = 1;
+PNGROUP = 2;
+sizeofLock = 4;
+aggr Lock
+{
+	'D' 0 val;
+};
+
+defn
+Lock(addr) {
+	complex Lock addr;
+	print("	val	", addr.val, "\n");
+};
+
+sizeofQLp = 12;
+aggr QLp
+{
+	'D' 0 inuse;
+	'A' QLp 4 next;
+	'C' 8 state;
+};
+
+defn
+QLp(addr) {
+	complex QLp addr;
+	print("	inuse	", addr.inuse, "\n");
+	print("	next	", addr.next\X, "\n");
+	print("	state	", addr.state, "\n");
+};
+
+sizeofQLock = 16;
+aggr QLock
+{
+	Lock 0 lock;
+	'D' 4 locked;
+	'A' QLp 8 $head;
+	'A' QLp 12 $tail;
+};
+
+defn
+QLock(addr) {
+	complex QLock addr;
+	print("Lock lock {\n");
+	Lock(addr.lock);
+	print("}\n");
+	print("	locked	", addr.locked, "\n");
+	print("	$head	", addr.$head\X, "\n");
+	print("	$tail	", addr.$tail\X, "\n");
+};
+
+sizeofRWLock = 20;
+aggr RWLock
+{
+	Lock 0 lock;
+	'D' 4 readers;
+	'D' 8 writer;
+	'A' QLp 12 $head;
+	'A' QLp 16 $tail;
+};
+
+defn
+RWLock(addr) {
+	complex RWLock addr;
+	print("Lock lock {\n");
+	Lock(addr.lock);
+	print("}\n");
+	print("	readers	", addr.readers, "\n");
+	print("	writer	", addr.writer, "\n");
+	print("	$head	", addr.$head\X, "\n");
+	print("	$tail	", addr.$tail\X, "\n");
+};
+
+RFNAMEG = 1;
+RFENVG = 2;
+RFFDG = 4;
+RFNOTEG = 8;
+RFPROC = 16;
+RFMEM = 32;
+RFNOWAIT = 64;
+RFCNAMEG = 1024;
+RFCENVG = 2048;
+RFCFDG = 4096;
+RFREND = 8192;
+sizeofQid = 8;
+aggr Qid
+{
+	'U' 0 path;
+	'U' 4 vers;
+};
+
+defn
+Qid(addr) {
+	complex Qid addr;
+	print("	path	", addr.path, "\n");
+	print("	vers	", addr.vers, "\n");
+};
+
+sizeofDir = 116;
+aggr Dir
+{
+	'a' 0 name;
+	'a' 28 uid;
+	'a' 56 gid;
+	Qid 84 qid;
+	'U' 92 mode;
+	'D' 96 atime;
+	'D' 100 mtime;
+	{
+	'V' 104 length;
+	{
+	'D' 104 llength;
+	'D' 108 hlength;
+	};
+	};
+	'u' 112 type;
+	'u' 114 dev;
+};
+
+defn
+Dir(addr) {
+	complex Dir addr;
+	print("	name	", addr.name, "\n");
+	print("	uid	", addr.uid, "\n");
+	print("	gid	", addr.gid, "\n");
+	print("Qid qid {\n");
+	Qid(addr.qid);
+	print("}\n");
+	print("	mode	", addr.mode, "\n");
+	print("	atime	", addr.atime, "\n");
+	print("	mtime	", addr.mtime, "\n");
+	print("_2_ {\n");
+		_2_(addr+104);
+	print("}\n");
+	print("	type	", addr.type, "\n");
+	print("	dev	", addr.dev, "\n");
+};
+
+sizeofWaitmsg = 112;
+aggr Waitmsg
+{
+	'a' 0 pid;
+	'a' 12 time;
+	'a' 48 msg;
+};
+
+defn
+Waitmsg(addr) {
+	complex Waitmsg addr;
+	print("	pid	", addr.pid, "\n");
+	print("	time	", addr.time, "\n");
+	print("	msg	", addr.msg, "\n");
+};
+
+Bsize = 8192;
+Bungetsize = 4;
+Bmagic = 3227993;
+Beof = -1;
+Bbad = -2;
+Binactive = 0;
+Bractive = 1;
+Bwactive = 2;
+Bracteof = 3;
+sizeofBiobufhdr = 52;
+aggr Biobufhdr
+{
+	'D' 0 icount;
+	'D' 4 ocount;
+	'D' 8 rdline;
+	'D' 12 runesize;
+	'D' 16 state;
+	'D' 20 fid;
+	'D' 24 flag;
+	'V' 28 offset;
+	'D' 36 bsize;
+	'X' 40 bbuf;
+	'X' 44 ebuf;
+	'X' 48 gbuf;
+};
+
+defn
+Biobufhdr(addr) {
+	complex Biobufhdr addr;
+	print("	icount	", addr.icount, "\n");
+	print("	ocount	", addr.ocount, "\n");
+	print("	rdline	", addr.rdline, "\n");
+	print("	runesize	", addr.runesize, "\n");
+	print("	state	", addr.state, "\n");
+	print("	fid	", addr.fid, "\n");
+	print("	flag	", addr.flag, "\n");
+	print("	offset	", addr.offset, "\n");
+	print("	bsize	", addr.bsize, "\n");
+	print("	bbuf	", addr.bbuf\X, "\n");
+	print("	ebuf	", addr.ebuf\X, "\n");
+	print("	gbuf	", addr.gbuf\X, "\n");
+};
+
+sizeofBiobuf = 8248;
+aggr Biobuf
+{
+	{
+	'D' 0 icount;
+	'D' 4 ocount;
+	'D' 8 rdline;
+	'D' 12 runesize;
+	'D' 16 state;
+	'D' 20 fid;
+	'D' 24 flag;
+	'V' 28 offset;
+	'D' 36 bsize;
+	'X' 40 bbuf;
+	'X' 44 ebuf;
+	'X' 48 gbuf;
+	};
+	'a' 52 b;
+};
+
+defn
+Biobuf(addr) {
+	complex Biobuf addr;
+	print("Biobufhdr {\n");
+		Biobufhdr(addr+0);
+	print("}\n");
+	print("	b	", addr.b, "\n");
+};
+
+sizeof_3_ = 4;
+aggr _3_
+{
+	'X' 0 sp;
+	'X' 0 rsp;
+};
+
+defn
+_3_(addr) {
+	complex _3_ addr;
+	print("	sp	", addr.sp\X, "\n");
+	print("	rsp	", addr.rsp\X, "\n");
+};
+
+sizeof_4_ = 4;
+aggr _4_
+{
+	'X' 0 ep;
+	'X' 0 rep;
+};
+
+defn
+_4_(addr) {
+	complex _4_ addr;
+	print("	ep	", addr.ep\X, "\n");
+	print("	rep	", addr.rep\X, "\n");
+};
+
+sizeofResub = 8;
+aggr Resub
+{
+	{
+	'X' 0 sp;
+	'X' 0 rsp;
+	};
+	{
+	'X' 4 ep;
+	'X' 4 rep;
+	};
+};
+
+defn
+Resub(addr) {
+	complex Resub addr;
+	print("_3_ {\n");
+		_3_(addr+0);
+	print("}\n");
+	print("_4_ {\n");
+		_4_(addr+4);
+	print("}\n");
+};
+
+sizeofReclass = 132;
+aggr Reclass
+{
+	'X' 0 end;
+	'a' 4 spans;
+};
+
+defn
+Reclass(addr) {
+	complex Reclass addr;
+	print("	end	", addr.end\X, "\n");
+	print("	spans	", addr.spans, "\n");
+};
+
+sizeof_5_ = 4;
+aggr _5_
+{
+	'A' Reclass 0 cp;
+	'u' 0 r;
+	'D' 0 subid;
+	'X' 0 right;
+};
+
+defn
+_5_(addr) {
+	complex _5_ addr;
+	print("	cp	", addr.cp\X, "\n");
+	print("	r	", addr.r, "\n");
+	print("	subid	", addr.subid, "\n");
+	print("	right	", addr.right\X, "\n");
+};
+
+sizeof_6_ = 4;
+aggr _6_
+{
+	'X' 0 left;
+	'X' 0 next;
+};
+
+defn
+_6_(addr) {
+	complex _6_ addr;
+	print("	left	", addr.left\X, "\n");
+	print("	next	", addr.next\X, "\n");
+};
+
+sizeofReinst = 12;
+aggr Reinst
+{
+	'D' 0 type;
+	{
+	'A' Reclass 4 cp;
+	'u' 4 r;
+	'D' 4 subid;
+	'A' Reinst 4 right;
+	};
+	{
+	'A' Reinst 8 left;
+	'A' Reinst 8 next;
+	};
+};
+
+defn
+Reinst(addr) {
+	complex Reinst addr;
+	print("	type	", addr.type, "\n");
+	print("_5_ {\n");
+		_5_(addr+4);
+	print("}\n");
+	print("_6_ {\n");
+		_6_(addr+8);
+	print("}\n");
+};
+
+sizeofReprog = 2176;
+aggr Reprog
+{
+	'A' Reinst 0 startinst;
+	'a' 4 class;
+	'a' 2116 firstinst;
+};
+
+defn
+Reprog(addr) {
+	complex Reprog addr;
+	print("	startinst	", addr.startinst\X, "\n");
+	print("	class	", addr.class, "\n");
+	print("	firstinst	", addr.firstinst, "\n");
+};
+
+complex Biobuf bout;
+sizeofBufblock = 16;
+aggr Bufblock
+{
+	'A' Bufblock 0 next;
+	'X' 4 start;
+	'X' 8 end;
+	'X' 12 current;
+};
+
+defn
+Bufblock(addr) {
+	complex Bufblock addr;
+	print("	next	", addr.next\X, "\n");
+	print("	start	", addr.start\X, "\n");
+	print("	end	", addr.end\X, "\n");
+	print("	current	", addr.current\X, "\n");
+};
+
+sizeofWord = 8;
+aggr Word
+{
+	'X' 0 s;
+	'A' Word 4 next;
+};
+
+defn
+Word(addr) {
+	complex Word addr;
+	print("	s	", addr.s\X, "\n");
+	print("	next	", addr.next\X, "\n");
+};
+
+sizeofEnvy = 8;
+aggr Envy
+{
+	'X' 0 name;
+	'A' Word 4 values;
+};
+
+defn
+Envy(addr) {
+	complex Envy addr;
+	print("	name	", addr.name\X, "\n");
+	print("	values	", addr.values\X, "\n");
+};
+
+complex Envy envy;
+sizeofRule = 44;
+aggr Rule
+{
+	'X' 0 target;
+	'A' Word 4 $tail;
+	'X' 8 recipe;
+	'd' 12 attr;
+	'd' 14 line;
+	'X' 16 file;
+	'A' Word 20 alltargets;
+	'D' 24 rule;
+	'A' Reprog 28 pat;
+	'X' 32 prog;
+	'A' Rule 36 chain;
+	'A' Rule 40 next;
+};
+
+defn
+Rule(addr) {
+	complex Rule addr;
+	print("	target	", addr.target\X, "\n");
+	print("	$tail	", addr.$tail\X, "\n");
+	print("	recipe	", addr.recipe\X, "\n");
+	print("	attr	", addr.attr, "\n");
+	print("	line	", addr.line, "\n");
+	print("	file	", addr.file\X, "\n");
+	print("	alltargets	", addr.alltargets\X, "\n");
+	print("	rule	", addr.rule, "\n");
+	print("	pat	", addr.pat\X, "\n");
+	print("	prog	", addr.prog\X, "\n");
+	print("	chain	", addr.chain\X, "\n");
+	print("	next	", addr.next\X, "\n");
+};
+
+complex Rule rules;
+complex Rule metarules;
+complex Rule patrule;
+sizeofArc = 64;
+aggr Arc
+{
+	'd' 0 flag;
+	'X' 4 n;
+	'A' Rule 8 r;
+	'X' 12 stem;
+	'X' 16 prog;
+	'a' 20 match;
+	'A' Arc 60 next;
+};
+
+defn
+Arc(addr) {
+	complex Arc addr;
+	print("	flag	", addr.flag, "\n");
+	print("	n	", addr.n\X, "\n");
+	print("	r	", addr.r\X, "\n");
+	print("	stem	", addr.stem\X, "\n");
+	print("	prog	", addr.prog\X, "\n");
+	print("	match	", addr.match, "\n");
+	print("	next	", addr.next\X, "\n");
+};
+
+sizeofNode = 20;
+aggr Node
+{
+	'X' 0 name;
+	'D' 4 time;
+	'u' 8 flags;
+	'A' Arc 12 prereqs;
+	'A' Node 16 next;
+};
+
+defn
+Node(addr) {
+	complex Node addr;
+	print("	name	", addr.name\X, "\n");
+	print("	time	", addr.time, "\n");
+	print("	flags	", addr.flags, "\n");
+	print("	prereqs	", addr.prereqs\X, "\n");
+	print("	next	", addr.next\X, "\n");
+};
+
+sizeofJob = 40;
+aggr Job
+{
+	'A' Rule 0 r;
+	'A' Node 4 n;
+	'X' 8 stem;
+	'X' 12 match;
+	'A' Word 16 p;
+	'A' Word 20 np;
+	'A' Word 24 t;
+	'A' Word 28 at;
+	'D' 32 nproc;
+	'A' Job 36 next;
+};
+
+defn
+Job(addr) {
+	complex Job addr;
+	print("	r	", addr.r\X, "\n");
+	print("	n	", addr.n\X, "\n");
+	print("	stem	", addr.stem\X, "\n");
+	print("	match	", addr.match\X, "\n");
+	print("	p	", addr.p\X, "\n");
+	print("	np	", addr.np\X, "\n");
+	print("	t	", addr.t\X, "\n");
+	print("	at	", addr.at\X, "\n");
+	print("	nproc	", addr.nproc, "\n");
+	print("	next	", addr.next\X, "\n");
+};
+
+complex Job jobs;
+sizeofSymtab = 16;
+aggr Symtab
+{
+	'd' 0 space;
+	'X' 4 name;
+	'X' 8 value;
+	'A' Symtab 12 next;
+};
+
+defn
+Symtab(addr) {
+	complex Symtab addr;
+	print("	space	", addr.space, "\n");
+	print("	name	", addr.name\X, "\n");
+	print("	value	", addr.value\X, "\n");
+	print("	next	", addr.next\X, "\n");
+};
+
+S_VAR = 0;
+S_TARGET = 1;
+S_TIME = 2;
+S_PID = 3;
+S_NODE = 4;
+S_AGG = 5;
+S_BITCH = 6;
+S_NOEXPORT = 7;
+S_OVERRIDE = 8;
+S_OUTOFDATE = 9;
+S_MAKEFILE = 10;
+S_MAKEVAR = 11;
+S_EXPORTED = 12;
+S_BULKED = 13;
+S_WESET = 14;
+S_INTERNAL = 15;
+complex Word readenv:w;
+complex Word encodenulls:w;
+complex Word encodenulls:$head;
+complex Envy exportenv:e;
+complex Word exportenv:w;
+complex Symtab exportenv:sy;
+complex Dir dirtime:d;
+complex Waitmsg waitfor:wm;
+complex Bufblock execsh:buf;
+complex Envy execsh:e;
+complex Envy pipecmd:e;
+complex Dir chgtime:sbuf;
+complex Resub rcopy:match;
+complex Dir mkdirstat:buf;
diff --git a/sys/src/cmd/mk/arc.c b/sys/src/cmd/mk/arc.c
new file mode 100755
index 000000000..5e0267ff8
--- /dev/null
+++ b/sys/src/cmd/mk/arc.c
@@ -0,0 +1,52 @@
+#include	"mk.h"
+
+Arc *
+newarc(Node *n, Rule *r, char *stem, Resub *match)
+{
+	Arc *a;
+
+	a = (Arc *)Malloc(sizeof(Arc));
+	a->n = n;
+	a->r = r;
+	a->stem = strdup(stem);
+	rcopy(a->match, match, NREGEXP);
+	a->next = 0;
+	a->flag = 0;
+	a->prog = r->prog;
+	return(a);
+}
+
+void
+dumpa(char *s, Arc *a)
+{
+	char buf[1024];
+
+	Bprint(&bout, "%sArc@%p: n=%p r=%p flag=0x%x stem='%s'",
+		s, a, a->n, a->r, a->flag, a->stem);
+	if(a->prog)
+		Bprint(&bout, " prog='%s'", a->prog);
+	Bprint(&bout, "\n");
+
+	if(a->n){
+		snprint(buf, sizeof(buf), "%s    ", (*s == ' ')? s:"");
+		dumpn(buf, a->n);
+	}
+}
+
+void
+nrep(void)
+{
+	Symtab *sym;
+	Word *w;
+
+	sym = symlook("NREP", S_VAR, 0);
+	if(sym){
+		w = sym->u.ptr;
+		if (w && w->s && *w->s)
+			nreps = atoi(w->s);
+	}
+	if(nreps < 1)
+		nreps = 1;
+	if(DEBUG(D_GRAPH))
+		Bprint(&bout, "nreps = %d\n", nreps);
+}
diff --git a/sys/src/cmd/mk/archive.c b/sys/src/cmd/mk/archive.c
new file mode 100755
index 000000000..70f7cc888
--- /dev/null
+++ b/sys/src/cmd/mk/archive.c
@@ -0,0 +1,166 @@
+#include	"mk.h"
+#include	<ar.h>
+
+static void atimes(char *);
+static char *split(char*, char**);
+
+long
+atimeof(int force, char *name)
+{
+	Symtab *sym;
+	long t;
+	char *archive, *member, buf[512];
+
+	archive = split(name, &member);
+	if(archive == 0)
+		Exit();
+
+	t = mtime(archive);
+	sym = symlook(archive, S_AGG, 0);
+	if(sym){
+		if(force || t > sym->u.value){
+			atimes(archive);
+			sym->u.value = t;
+		}
+	}
+	else{
+		atimes(archive);
+		/* mark the aggegate as having been done */
+		symlook(strdup(archive), S_AGG, "")->u.value = t;
+	}
+		/* truncate long member name to sizeof of name field in archive header */
+	snprint(buf, sizeof(buf), "%s(%.*s)", archive, utfnlen(member, SARNAME), member);
+	sym = symlook(buf, S_TIME, 0);
+	if (sym)
+		return sym->u.value;
+	return 0;
+}
+
+void
+atouch(char *name)
+{
+	char *archive, *member;
+	int fd, i;
+	struct ar_hdr h;
+	long t;
+
+	archive = split(name, &member);
+	if(archive == 0)
+		Exit();
+
+	fd = open(archive, ORDWR);
+	if(fd < 0){
+		fd = create(archive, OWRITE, 0666);
+		if(fd < 0){
+			perror(archive);
+			Exit();
+		}
+		write(fd, ARMAG, SARMAG);
+	}
+	if(symlook(name, S_TIME, 0)){
+		/* hoon off and change it in situ */
+		LSEEK(fd, SARMAG, 0);
+		while(read(fd, (char *)&h, sizeof(h)) == sizeof(h)){
+			for(i = SARNAME-1; i > 0 && h.name[i] == ' '; i--)
+					;
+			h.name[i+1]=0;
+			if(strcmp(member, h.name) == 0){
+				t = SARNAME-sizeof(h);	/* ughgghh */
+				LSEEK(fd, t, 1);
+				fprint(fd, "%-12ld", time(0));
+				break;
+			}
+			t = atol(h.size);
+			if(t&01) t++;
+			LSEEK(fd, t, 1);
+		}
+	}
+	close(fd);
+}
+
+static void
+atimes(char *ar)
+{
+	struct ar_hdr h;
+	long at, t;
+	int fd, i;
+	char buf[BIGBLOCK];
+	Dir *d;
+	
+	fd = open(ar, OREAD);
+	if(fd < 0)
+		return;
+
+	if(read(fd, buf, SARMAG) != SARMAG){
+		close(fd);
+		return;
+	}
+	if((d = dirfstat(fd)) == nil){
+		close(fd);
+		return;
+	}
+	at = d->mtime;
+	free(d);
+	while(read(fd, (char *)&h, sizeof(h)) == sizeof(h)){
+		t = atol(h.date);
+		if(t >= at)	/* new things in old archives confuses mk */
+			t = at-1;
+		if(t <= 0)	/* as it sometimes happens; thanks ken */
+			t = 1;
+		for(i = sizeof(h.name)-1; i > 0 && h.name[i] == ' '; i--)
+			;
+		if(h.name[i] == '/')		/* system V bug */
+			i--;
+		h.name[i+1]=0;		/* can stomp on date field */
+		snprint(buf, sizeof buf, "%s(%s)", ar, h.name);
+		symlook(strdup(buf), S_TIME, (void*)t)->u.value = t;
+		t = atol(h.size);
+		if(t&01) t++;
+		LSEEK(fd, t, 1);
+	}
+	close(fd);
+}
+
+static int
+type(char *file)
+{
+	int fd;
+	char buf[SARMAG];
+
+	fd = open(file, OREAD);
+	if(fd < 0){
+		if(symlook(file, S_BITCH, 0) == 0){
+			Bprint(&bout, "%s doesn't exist: assuming it will be an archive\n", file);
+			symlook(file, S_BITCH, (void *)file);
+		}
+		return 1;
+	}
+	if(read(fd, buf, SARMAG) != SARMAG){
+		close(fd);
+		return 0;
+	}
+	close(fd);
+	return !strncmp(ARMAG, buf, SARMAG);
+}
+
+static char*
+split(char *name, char **member)
+{
+	char *p, *q;
+
+	p = strdup(name);
+	q = utfrune(p, '(');
+	if(q){
+		*q++ = 0;
+		if(member)
+			*member = q;
+		q = utfrune(q, ')');
+		if (q)
+			*q = 0;
+		if(type(p))
+			return p;
+		free(p);
+		fprint(2, "mk: '%s' is not an archive\n", name);
+	}
+	return 0;
+}
diff --git a/sys/src/cmd/mk/bufblock.c b/sys/src/cmd/mk/bufblock.c
new file mode 100755
index 000000000..979403bca
--- /dev/null
+++ b/sys/src/cmd/mk/bufblock.c
@@ -0,0 +1,88 @@
+#include	"mk.h"
+
+static Bufblock *freelist;
+#define	QUANTA	4096
+
+Bufblock *
+newbuf(void)
+{
+	Bufblock *p;
+
+	if (freelist) {
+		p = freelist;
+		freelist = freelist->next;
+	} else {
+		p = (Bufblock *) Malloc(sizeof(Bufblock));
+		p->start = Malloc(QUANTA*sizeof(*p->start));
+		p->end = p->start+QUANTA;
+	}
+	p->current = p->start;
+	*p->start = 0;
+	p->next = 0;
+	return p;
+}
+
+void
+freebuf(Bufblock *p)
+{
+	p->next = freelist;
+	freelist = p;
+}
+
+void
+growbuf(Bufblock *p)
+{
+	int n;
+	Bufblock *f;
+	char *cp;
+
+	n = p->end-p->start+QUANTA;
+		/* search the free list for a big buffer */
+	for (f = freelist; f; f = f->next) {
+		if (f->end-f->start >= n) {
+			memcpy(f->start, p->start, p->end-p->start);
+			cp = f->start;
+			f->start = p->start;
+			p->start = cp;
+			cp = f->end;
+			f->end = p->end;
+			p->end = cp;
+			f->current = f->start;
+			break;
+		}
+	}
+	if (!f) {		/* not found - grow it */
+		p->start = Realloc(p->start, n);
+		p->end = p->start+n;
+	}
+	p->current = p->start+n-QUANTA;
+}
+
+void
+bufcpy(Bufblock *buf, char *cp, int n)
+{
+
+	while (n--)
+		insert(buf, *cp++);
+}
+
+void
+insert(Bufblock *buf, int c)
+{
+
+	if (buf->current >= buf->end)
+		growbuf(buf);
+	*buf->current++ = c;
+}
+
+void
+rinsert(Bufblock *buf, Rune r)
+{
+	int n;
+
+	n = runelen(r);
+	if (buf->current+n > buf->end)
+		growbuf(buf);
+	runetochar(buf->current, &r);
+	buf->current += n;
+}
diff --git a/sys/src/cmd/mk/env.c b/sys/src/cmd/mk/env.c
new file mode 100755
index 000000000..767621229
--- /dev/null
+++ b/sys/src/cmd/mk/env.c
@@ -0,0 +1,149 @@
+#include	"mk.h"
+
+enum {
+	ENVQUANTA=10
+};
+
+Envy	*envy;
+static int nextv;
+
+static char	*myenv[] =
+{
+	"target",
+	"stem",
+	"prereq",
+	"pid",
+	"nproc",
+	"newprereq",
+	"alltarget",
+	"newmember",
+	"stem0",		/* must be in order from here */
+	"stem1",
+	"stem2",
+	"stem3",
+	"stem4",
+	"stem5",
+	"stem6",
+	"stem7",
+	"stem8",
+	"stem9",
+	0,
+};
+
+void
+initenv(void)
+{
+	char **p;
+
+	for(p = myenv; *p; p++)
+		symlook(*p, S_INTERNAL, (void *)"");
+	readenv();				/* o.s. dependent */
+}
+
+static void
+envinsert(char *name, Word *value)
+{
+	static int envsize;
+
+	if (nextv >= envsize) {
+		envsize += ENVQUANTA;
+		envy = (Envy *) Realloc((char *) envy, envsize*sizeof(Envy));
+	}
+	envy[nextv].name = name;
+	envy[nextv++].values = value;
+}
+
+static void
+envupd(char *name, Word *value)
+{
+	Envy *e;
+
+	for(e = envy; e->name; e++)
+		if(strcmp(name, e->name) == 0){
+			delword(e->values);
+			e->values = value;
+			return;
+		}
+	e->name = name;
+	e->values = value;
+	envinsert(0,0);
+}
+
+static void
+ecopy(Symtab *s)
+{
+	char **p;
+
+	if(symlook(s->name, S_NOEXPORT, 0))
+		return;
+	for(p = myenv; *p; p++)
+		if(strcmp(*p, s->name) == 0)
+			return;
+	envinsert(s->name, s->u.ptr);
+}
+
+void
+execinit(void)
+{
+	char **p;
+
+	nextv = 0;
+	for(p = myenv; *p; p++)
+		envinsert(*p, stow(""));
+
+	symtraverse(S_VAR, ecopy);
+	envinsert(0, 0);
+}
+
+Envy*
+buildenv(Job *j, int slot)
+{
+	char **p, *cp, *qp;
+	Word *w, *v, **l;
+	int i;
+	char buf[256];
+
+	envupd("target", wdup(j->t));
+	if(j->r->attr&REGEXP)
+		envupd("stem",newword(""));
+	else
+		envupd("stem", newword(j->stem));
+	envupd("prereq", wdup(j->p));
+	snprint(buf, sizeof buf, "%d", getpid());
+	envupd("pid", newword(buf));
+	snprint(buf, sizeof buf, "%d", slot);
+	envupd("nproc", newword(buf));
+	envupd("newprereq", wdup(j->np));
+	envupd("alltarget", wdup(j->at));
+	l = &v;
+	v = w = wdup(j->np);
+	while(w){
+		cp = strchr(w->s, '(');
+		if(cp){
+			qp = strchr(cp+1, ')');
+			if(qp){
+				*qp = 0;
+				strcpy(w->s, cp+1);
+				l = &w->next;
+				w = w->next;
+				continue;
+			}
+		}
+		*l = w->next;
+		free(w->s);
+		free(w);
+		w = *l;
+	}
+	envupd("newmember", v);
+		/* update stem0 -> stem9 */
+	for(p = myenv; *p; p++)
+		if(strcmp(*p, "stem0") == 0)
+			break;
+	for(i = 0; *p; i++, p++){
+		if((j->r->attr&REGEXP) && j->match[i])
+			envupd(*p, newword(j->match[i]));
+		else 
+			envupd(*p, newword(""));
+	}
+	return envy;
+}
diff --git a/sys/src/cmd/mk/file.c b/sys/src/cmd/mk/file.c
new file mode 100755
index 000000000..5ddebba43
--- /dev/null
+++ b/sys/src/cmd/mk/file.c
@@ -0,0 +1,89 @@
+#include	"mk.h"
+
+/* table-driven version in bootes dump of 12/31/96 */
+
+long
+mtime(char *name)
+{
+	return mkmtime(name, 1);
+}
+
+long
+timeof(char *name, int force)
+{
+	Symtab *sym;
+	long t;
+
+	if(utfrune(name, '('))
+		return atimeof(force, name);		/* archive */
+
+	if(force)
+		return mtime(name);
+
+	sym = symlook(name, S_TIME, 0);
+	if (sym)
+		return sym->u.value;		/* uggh */
+
+	t = mkmtime(name, 0);
+	if(t == 0)
+		return 0;
+
+	symlook(name, S_TIME, (void*)t);		/* install time in cache */
+	return t;
+}
+
+void
+touch(char *name)
+{
+	Bprint(&bout, "touch(%s)\n", name);
+	if(nflag)
+		return;
+
+	if(utfrune(name, '('))
+		atouch(name);		/* archive */
+	else if(chgtime(name) < 0) {
+		perror(name);
+		Exit();
+	}
+}
+
+void
+delete(char *name)
+{
+	if(utfrune(name, '(') == 0) {		/* file */
+		if(remove(name) < 0)
+			perror(name);
+	} else
+		fprint(2, "hoon off; mk can'tdelete archive members\n");
+}
+
+void
+timeinit(char *s)
+{
+	long t;
+	char *cp;
+	Rune r;
+	int c, n;
+
+	t = time(0);
+	while (*s) {
+		cp = s;
+		do{
+			n = chartorune(&r, s);
+			if (r == ' ' || r == ',' || r == '\n')
+				break;
+			s += n;
+		} while(*s);
+		c = *s;
+		*s = 0;
+		symlook(strdup(cp), S_TIME, (void *)t)->u.value = t;
+		if (c)
+			*s++ = c;
+		while(*s){
+			n = chartorune(&r, s);
+			if(r != ' ' && r != ',' && r != '\n')
+				break;
+			s += n;
+		}
+	}
+}
diff --git a/sys/src/cmd/mk/fns.h b/sys/src/cmd/mk/fns.h
new file mode 100755
index 000000000..e25d90c1c
--- /dev/null
+++ b/sys/src/cmd/mk/fns.h
@@ -0,0 +1,82 @@
+void	addrule(char*, Word*, char*, Word*, int, int, char*);
+void	addrules(Word*, Word*, char*, int, int, char*);
+void	addw(Word*, char*);
+int	assline(Biobuf *, Bufblock *);
+long	atimeof(int,char*);
+void	atouch(char*);
+void	bufcpy(Bufblock *, char *, int);
+Envy	*buildenv(Job*, int);
+void	catchnotes(void);
+char 	*charin(char *, char *);
+int	chgtime(char*);
+void	clrmade(Node*);
+char	*copyq(char*, Rune, Bufblock*);
+void	delete(char*);
+void	delword(Word*);
+int	dorecipe(Node*);
+void	dumpa(char*, Arc*);
+void	dumpj(char*, Job*, int);
+void	dumpn(char*, Node*);
+void	dumpr(char*, Rule*);
+void	dumpv(char*);
+void	dumpw(char*, Word*);
+int	escapetoken(Biobuf*, Bufblock*, int, int);
+void	execinit(void);
+int	execsh(char*, char*, Bufblock*, Envy*);
+void	Exit(void);
+char	*expandquote(char*, Rune, Bufblock*);
+void	expunge(int, char*);
+void	freebuf(Bufblock*);
+void	front(char*);
+Node	*graph(char*);
+void	growbuf(Bufblock *);
+void	initenv(void);
+void	insert(Bufblock *, int);
+void	ipop(void);
+void	ipush(void);
+void	killchildren(char*);
+void	*Malloc(int);
+char	*maketmp(void);
+int	match(char*, char*, char*);
+void	mk(char*);
+ulong	mkmtime(char*, int);
+long	mtime(char*);
+Arc	*newarc(Node*, Rule*, char*, Resub*);
+Bufblock *newbuf(void);
+Job	*newjob(Rule*, Node*, char*, char**, Word*, Word*, Word*, Word*);
+Word	*newword(char*);
+int	nextrune(Biobuf*, int);
+int	nextslot(void);
+void	nproc(void);
+void	nrep(void);
+int	outofdate(Node*, Arc*, int);
+void	parse(char*, int, int);
+int	pipecmd(char*, Envy*, int*);
+void	prusage(void);
+void	rcopy(char**, Resub*, int);
+void	readenv(void);
+void	*Realloc(void*, int);
+void	rinsert(Bufblock *, Rune);
+char	*rulecnt(void);
+void	run(Job*);
+void	setvar(char*, void*);
+char	*shname(char*);
+void	shprint(char*, Envy*, Bufblock*);
+Word	*stow(char*);
+void	subst(char*, char*, char*, int);
+void	symdel(char*, int);
+void	syminit(void);
+Symtab	*symlook(char*, int, void*);
+void	symstat(void);
+void	symtraverse(int, void(*)(Symtab*));
+void	timeinit(char*);
+long	timeof(char*, int);
+void	touch(char*);
+void	update(int, Node*);
+void	usage(void);
+Word	*varsub(char**);
+int	waitfor(char*);
+int	waitup(int, int*);
+Word	*wdup(Word*);
+int	work(Node*, Node*, Arc*);
+char	*wtos(Word*, int);
diff --git a/sys/src/cmd/mk/graph.c b/sys/src/cmd/mk/graph.c
new file mode 100755
index 000000000..87217afc6
--- /dev/null
+++ b/sys/src/cmd/mk/graph.c
@@ -0,0 +1,279 @@
+#include	"mk.h"
+
+static Node *applyrules(char *, char *);
+static void togo(Node *);
+static int vacuous(Node *);
+static Node *newnode(char *);
+static void trace(char *, Arc *);
+static void cyclechk(Node *);
+static void ambiguous(Node *);
+static void attribute(Node *);
+
+Node *
+graph(char *target)
+{
+	Node *node;
+	char *cnt;
+
+	cnt = rulecnt();
+	node = applyrules(target, cnt);
+	free(cnt);
+	cyclechk(node);
+	node->flags |= PROBABLE;	/* make sure it doesn't get deleted */
+	vacuous(node);
+	ambiguous(node);
+	attribute(node);
+	return(node);
+}
+
+static Node *
+applyrules(char *target, char *cnt)
+{
+	Symtab *sym;
+	Node *node;
+	Rule *r;
+	Arc head, *a = &head;
+	Word *w;
+	char stem[NAMEBLOCK], buf[NAMEBLOCK];
+	Resub rmatch[NREGEXP];
+
+/*	print("applyrules(%lux='%s')\n", target, target);/**/
+	sym = symlook(target, S_NODE, 0);
+	if(sym)
+		return sym->u.ptr;
+	target = strdup(target);
+	node = newnode(target);
+	head.n = 0;
+	head.next = 0;
+	sym = symlook(target, S_TARGET, 0);
+	memset((char*)rmatch, 0, sizeof(rmatch));
+	for(r = sym? sym->u.ptr:0; r; r = r->chain){
+		if(r->attr&META) continue;
+		if(strcmp(target, r->target)) continue;
+		if((!r->recipe || !*r->recipe) && (!r->tail || !r->tail->s || !*r->tail->s)) continue;	/* no effect; ignore */
+		if(cnt[r->rule] >= nreps) continue;
+		cnt[r->rule]++;
+		node->flags |= PROBABLE;
+
+/*		if(r->attr&VIR)
+ *			node->flags |= VIRTUAL;
+ *		if(r->attr&NOREC)
+ *			node->flags |= NORECIPE;
+ *		if(r->attr&DEL)
+ *			node->flags |= DELETE;
+ */
+		if(!r->tail || !r->tail->s || !*r->tail->s) {
+			a->next = newarc((Node *)0, r, "", rmatch);
+			a = a->next;
+		} else
+			for(w = r->tail; w; w = w->next){
+				a->next = newarc(applyrules(w->s, cnt), r, "", rmatch);
+				a = a->next;
+		}
+		cnt[r->rule]--;
+		head.n = node;
+	}
+	for(r = metarules; r; r = r->next){
+		if((!r->recipe || !*r->recipe) && (!r->tail || !r->tail->s || !*r->tail->s)) continue;	/* no effect; ignore */
+		if ((r->attr&NOVIRT) && a != &head && (a->r->attr&VIR))
+			continue;
+		if(r->attr&REGEXP){
+			stem[0] = 0;
+			patrule = r;
+			memset((char*)rmatch, 0, sizeof(rmatch));
+			if(regexec(r->pat, node->name, rmatch, NREGEXP) == 0)
+				continue;
+		} else {
+			if(!match(node->name, r->target, stem)) continue;
+		}
+		if(cnt[r->rule] >= nreps) continue;
+		cnt[r->rule]++;
+
+/*		if(r->attr&VIR)
+ *			node->flags |= VIRTUAL;
+ *		if(r->attr&NOREC)
+ *			node->flags |= NORECIPE;
+ *		if(r->attr&DEL)
+ *			node->flags |= DELETE;
+ */
+		if(!r->tail || !r->tail->s || !*r->tail->s) {
+			a->next = newarc((Node *)0, r, stem, rmatch);
+			a = a->next;
+		} else
+			for(w = r->tail; w; w = w->next){
+				if(r->attr&REGEXP)
+					regsub(w->s, buf, sizeof(buf), rmatch, NREGEXP);
+				else
+					subst(stem, w->s, buf, sizeof(buf));
+				a->next = newarc(applyrules(buf, cnt), r, stem, rmatch);
+				a = a->next;
+			}
+		cnt[r->rule]--;
+	}
+	a->next = node->prereqs;
+	node->prereqs = head.next;
+	return(node);
+}
+
+static void
+togo(Node *node)
+{
+	Arc *la, *a;
+
+	/* delete them now */
+	la = 0;
+	for(a = node->prereqs; a; la = a, a = a->next)
+		if(a->flag&TOGO){
+			if(a == node->prereqs)
+				node->prereqs = a->next;
+			else
+				la->next = a->next, a = la;
+		}
+}
+
+static
+vacuous(Node *node)
+{
+	Arc *la, *a;
+	int vac = !(node->flags&PROBABLE);
+
+	if(node->flags&READY)
+		return(node->flags&VACUOUS);
+	node->flags |= READY;
+	for(a = node->prereqs; a; a = a->next)
+		if(a->n && vacuous(a->n) && (a->r->attr&META))
+			a->flag |= TOGO;
+		else
+			vac = 0;
+	/* if a rule generated arcs that DON'T go; no others from that rule go */
+	for(a = node->prereqs; a; a = a->next)
+		if((a->flag&TOGO) == 0)
+			for(la = node->prereqs; la; la = la->next)
+				if((la->flag&TOGO) && (la->r == a->r)){
+					la->flag &= ~TOGO;
+				}
+	togo(node);
+	if(vac)
+		node->flags |= VACUOUS;
+	return(vac);
+}
+
+static Node *
+newnode(char *name)
+{
+	register Node *node;
+
+	node = (Node *)Malloc(sizeof(Node));
+	symlook(name, S_NODE, (void *)node);
+	node->name = name;
+	node->time = timeof(name, 0);
+	node->prereqs = 0;
+	node->flags = node->time? PROBABLE : 0;
+	node->next = 0;
+	return(node);
+}
+
+void
+dumpn(char *s, Node *n)
+{
+	char buf[1024];
+	Arc *a;
+
+	Bprint(&bout, "%s%s@%p: time=%ld flags=0x%x next=%p\n",
+		s, n->name, n, n->time, n->flags, n->next);
+	for(a = n->prereqs; a; a = a->next){
+		snprint(buf, sizeof buf, "%s   ", (*s == ' ')? s:"");
+		dumpa(buf, a);
+	}
+}
+
+static void
+trace(char *s, Arc *a)
+{
+	fprint(2, "\t%s", s);
+	while(a){
+		fprint(2, " <-(%s:%d)- %s", a->r->file, a->r->line,
+			a->n? a->n->name:"");
+		if(a->n){
+			for(a = a->n->prereqs; a; a = a->next)
+				if(*a->r->recipe) break;
+		} else
+			a = 0;
+	}
+	fprint(2, "\n");
+}
+
+static void
+cyclechk(Node *n)
+{
+	Arc *a;
+
+	if((n->flags&CYCLE) && n->prereqs){
+		fprint(2, "mk: cycle in graph detected at target %s\n", n->name);
+		Exit();
+	}
+	n->flags |= CYCLE;
+	for(a = n->prereqs; a; a = a->next)
+		if(a->n)
+			cyclechk(a->n);
+	n->flags &= ~CYCLE;
+}
+
+static void
+ambiguous(Node *n)
+{
+	Arc *a;
+	Rule *r = 0;
+	Arc *la;
+	int bad = 0;
+
+	la = 0;
+	for(a = n->prereqs; a; a = a->next){
+		if(a->n)
+			ambiguous(a->n);
+		if(*a->r->recipe == 0) continue;
+		if(r == 0)
+			r = a->r, la = a;
+		else{
+			if(r->recipe != a->r->recipe){
+				if((r->attr&META) && !(a->r->attr&META)){
+					la->flag |= TOGO;
+					r = a->r, la = a;
+				} else if(!(r->attr&META) && (a->r->attr&META)){
+					a->flag |= TOGO;
+					continue;
+				}
+			}
+			if(r->recipe != a->r->recipe){
+				if(bad == 0){
+					fprint(2, "mk: ambiguous recipes for %s:\n", n->name);
+					bad = 1;
+					trace(n->name, la);
+				}
+				trace(n->name, a);
+			}
+		}
+	}
+	if(bad)
+		Exit();
+	togo(n);
+}
+
+static void
+attribute(Node *n)
+{
+	register Arc *a;
+
+	for(a = n->prereqs; a; a = a->next){
+		if(a->r->attr&VIR)
+			n->flags |= VIRTUAL;
+		if(a->r->attr&NOREC)
+			n->flags |= NORECIPE;
+		if(a->r->attr&DEL)
+			n->flags |= DELETE;
+		if(a->n)
+			attribute(a->n);
+	}
+	if(n->flags&VIRTUAL)
+		n->time = 0;
+}
diff --git a/sys/src/cmd/mk/job.c b/sys/src/cmd/mk/job.c
new file mode 100755
index 000000000..a8266667f
--- /dev/null
+++ b/sys/src/cmd/mk/job.c
@@ -0,0 +1,33 @@
+#include	"mk.h"
+
+Job *
+newjob(Rule *r, Node *nlist, char *stem, char **match, Word *pre, Word *npre, Word *tar, Word *atar)
+{
+	register Job *j;
+
+	j = (Job *)Malloc(sizeof(Job));
+	j->r = r;
+	j->n = nlist;
+	j->stem = stem;
+	j->match = match;
+	j->p = pre;
+	j->np = npre;
+	j->t = tar;
+	j->at = atar;
+	j->nproc = -1;
+	j->next = 0;
+	return(j);
+}
+
+void
+dumpj(char *s, Job *j, int all)
+{
+	Bprint(&bout, "%s\n", s);
+	while(j){
+		Bprint(&bout, "job@%p: r=%p n=%p stem='%s' nproc=%d\n",
+			j, j->r, j->n, j->stem, j->nproc);
+		Bprint(&bout, "\ttarget='%s' alltarget='%s' prereq='%s' nprereq='%s'\n",
+			wtos(j->t, ' '), wtos(j->at, ' '), wtos(j->p, ' '), wtos(j->np, ' '));
+		j = all? j->next : 0;
+	}
+}
diff --git a/sys/src/cmd/mk/lex.c b/sys/src/cmd/mk/lex.c
new file mode 100755
index 000000000..d942918f3
--- /dev/null
+++ b/sys/src/cmd/mk/lex.c
@@ -0,0 +1,133 @@
+#include	"mk.h"
+
+static	int	bquote(Biobuf*, Bufblock*);
+
+/*
+ *	Assemble a line skipping blank lines, comments, and eliding
+ *	escaped newlines
+ */
+int
+assline(Biobuf *bp, Bufblock *buf)
+{
+	int c;
+	int lastc;
+
+	buf->current=buf->start;
+	while ((c = nextrune(bp, 1)) >= 0){
+		switch(c)
+		{
+		case '\r':		/* consumes CRs for Win95 */
+			continue;
+		case '\n':
+			if (buf->current != buf->start) {
+				insert(buf, 0);
+				return 1;
+			}
+			break;		/* skip empty lines */
+		case '\\':
+		case '\'':
+		case '"':
+			rinsert(buf, c);
+			if (escapetoken(bp, buf, 1, c) == 0)
+				Exit();
+			break;
+		case '`':
+			if (bquote(bp, buf) == 0)
+				Exit();
+			break;
+		case '#':
+			lastc = '#';
+			while ((c = Bgetc(bp)) != '\n') {
+				if (c < 0)
+					goto eof;
+				if(c != '\r')
+					lastc = c;
+			}
+			mkinline++;
+			if (lastc == '\\')
+				break;		/* propagate escaped newlines??*/
+			if (buf->current != buf->start) {
+				insert(buf, 0);
+				return 1;
+			}
+			break;
+		default:
+			rinsert(buf, c);
+			break;
+		}
+	}
+eof:
+	insert(buf, 0);
+	return *buf->start != 0;
+}
+
+/*
+ *	assemble a back-quoted shell command into a buffer
+ */
+static int
+bquote(Biobuf *bp, Bufblock *buf)
+{
+	int c, line, term;
+	int start;
+
+	line = mkinline;
+	while((c = Bgetrune(bp)) == ' ' || c == '\t')
+			;
+	if(c == '{'){
+		term = '}';		/* rc style */
+		while((c = Bgetrune(bp)) == ' ' || c == '\t')
+			;
+	} else
+		term = '`';		/* sh style */
+
+	start = buf->current-buf->start;
+	for(;c > 0; c = nextrune(bp, 0)){
+		if(c == term){
+			insert(buf, '\n');
+			insert(buf,0);
+			buf->current = buf->start+start;
+			execinit();
+			execsh(0, buf->current, buf, envy);
+			return 1;
+		}
+		if(c == '\n')
+			break;
+		if(c == '\'' || c == '"' || c == '\\'){
+			insert(buf, c);
+			if(!escapetoken(bp, buf, 1, c))
+				return 0;
+			continue;
+		}
+		rinsert(buf, c);
+	}
+	SYNERR(line);
+	fprint(2, "missing closing %c after `\n", term);
+	return 0;
+}
+
+/*
+ *	get next character stripping escaped newlines
+ *	the flag specifies whether escaped newlines are to be elided or
+ *	replaced with a blank.
+ */
+int
+nextrune(Biobuf *bp, int elide)
+{
+	int c;
+
+	for (;;) {
+		c = Bgetrune(bp);
+		if (c == '\\') {
+			if (Bgetrune(bp) == '\n') {
+				mkinline++;
+				if (elide)
+					continue;
+				return ' ';
+			}
+			Bungetrune(bp);
+		}
+		if (c == '\n')
+			mkinline++;
+		return c;
+	}
+}
diff --git a/sys/src/cmd/mk/main.c b/sys/src/cmd/mk/main.c
new file mode 100755
index 000000000..08bb3ab26
--- /dev/null
+++ b/sys/src/cmd/mk/main.c
@@ -0,0 +1,281 @@
+#include	"mk.h"
+
+#define		MKFILE		"mkfile"
+
+static char *version = "@(#)mk general release 4 (plan 9)";
+int debug;
+Rule *rules, *metarules;
+int nflag = 0;
+int tflag = 0;
+int iflag = 0;
+int kflag = 0;
+int aflag = 0;
+int uflag = 0;
+char *explain = 0;
+Word *target1;
+int nreps = 1;
+Job *jobs;
+Biobuf bout;
+Rule *patrule;
+void badusage(void);
+#ifdef	PROF
+short buf[10000];
+#endif
+
+void
+main(int argc, char **argv)
+{
+	Word *w;
+	char *s, *temp;
+	char *files[256], **f = files, **ff;
+	int sflag = 0;
+	int i;
+	int tfd = -1;
+	Biobuf tb;
+	Bufblock *buf;
+	Bufblock *whatif;
+
+	/*
+	 *  start with a copy of the current environment variables
+	 *  instead of sharing them
+	 */
+
+	Binit(&bout, 1, OWRITE);
+	buf = newbuf();
+	whatif = 0;
+	USED(argc);
+	for(argv++; *argv && (**argv == '-'); argv++)
+	{
+		bufcpy(buf, argv[0], strlen(argv[0]));
+		insert(buf, ' ');
+		switch(argv[0][1])
+		{
+		case 'a':
+			aflag = 1;
+			break;
+		case 'd':
+			if(*(s = &argv[0][2]))
+				while(*s) switch(*s++)
+				{
+				case 'p':	debug |= D_PARSE; break;
+				case 'g':	debug |= D_GRAPH; break;
+				case 'e':	debug |= D_EXEC; break;
+				}
+			else
+				debug = 0xFFFF;
+			break;
+		case 'e':
+			explain = &argv[0][2];
+			break;
+		case 'f':
+			if(*++argv == 0)
+				badusage();
+			*f++ = *argv;
+			bufcpy(buf, argv[0], strlen(argv[0]));
+			insert(buf, ' ');
+			break;
+		case 'i':
+			iflag = 1;
+			break;
+		case 'k':
+			kflag = 1;
+			break;
+		case 'n':
+			nflag = 1;
+			break;
+		case 's':
+			sflag = 1;
+			break;
+		case 't':
+			tflag = 1;
+			break;
+		case 'u':
+			uflag = 1;
+			break;
+		case 'w':
+			if(whatif == 0)
+				whatif = newbuf();
+			else
+				insert(whatif, ' ');
+			if(argv[0][2])
+				bufcpy(whatif, &argv[0][2], strlen(&argv[0][2]));
+			else {
+				if(*++argv == 0)
+					badusage();
+				bufcpy(whatif, &argv[0][0], strlen(&argv[0][0]));
+			}
+			break;
+		default:
+			badusage();
+		}
+	}
+#ifdef	PROF
+	{
+		extern etext();
+		monitor(main, etext, buf, sizeof buf, 300);
+	}
+#endif
+
+	if(aflag)
+		iflag = 1;
+	usage();
+	syminit();
+	initenv();
+	usage();
+
+	/*
+		assignment args become null strings
+	*/
+	temp = 0;
+	for(i = 0; argv[i]; i++) if(utfrune(argv[i], '=')){
+		bufcpy(buf, argv[i], strlen(argv[i]));
+		insert(buf, ' ');
+		if(tfd < 0){
+			temp = maketmp();
+			if(temp == 0) {
+				perror("temp file");
+				Exit();
+			}
+			if((tfd = create(temp, ORDWR, 0600)) < 0){
+				perror(temp);
+				Exit();
+			}
+			Binit(&tb, tfd, OWRITE);
+		}
+		Bprint(&tb, "%s\n", argv[i]);
+		*argv[i] = 0;
+	}
+	if(tfd >= 0){
+		Bflush(&tb);
+		LSEEK(tfd, 0L, 0);
+		parse("command line args", tfd, 1);
+		remove(temp);
+	}
+
+	if (buf->current != buf->start) {
+		buf->current--;
+		insert(buf, 0);
+	}
+	symlook("MKFLAGS", S_VAR, (void *) stow(buf->start));
+	buf->current = buf->start;
+	for(i = 0; argv[i]; i++){
+		if(*argv[i] == 0) continue;
+		if(i)
+			insert(buf, ' ');
+		bufcpy(buf, argv[i], strlen(argv[i]));
+	}
+	insert(buf, 0);
+	symlook("MKARGS", S_VAR, (void *) stow(buf->start));
+	freebuf(buf);
+
+	if(f == files){
+		if(access(MKFILE, 4) == 0)
+			parse(MKFILE, open(MKFILE, 0), 0);
+	} else
+		for(ff = files; ff < f; ff++)
+			parse(*ff, open(*ff, 0), 0);
+	if(DEBUG(D_PARSE)){
+		dumpw("default targets", target1);
+		dumpr("rules", rules);
+		dumpr("metarules", metarules);
+		dumpv("variables");
+	}
+	if(whatif){
+		insert(whatif, 0);
+		timeinit(whatif->start);
+		freebuf(whatif);
+	}
+	execinit();
+	/* skip assignment args */
+	while(*argv && (**argv == 0))
+		argv++;
+
+	catchnotes();
+	if(*argv == 0){
+		if(target1)
+			for(w = target1; w; w = w->next)
+				mk(w->s);
+		else {
+			fprint(2, "mk: nothing to mk\n");
+			Exit();
+		}
+	} else {
+		if(sflag){
+			for(; *argv; argv++)
+				if(**argv)
+					mk(*argv);
+		} else {
+			Word *head, *tail, *t;
+
+			/* fake a new rule with all the args as prereqs */
+			tail = 0;
+			t = 0;
+			for(; *argv; argv++)
+				if(**argv){
+					if(tail == 0)
+						tail = t = newword(*argv);
+					else {
+						t->next = newword(*argv);
+						t = t->next;
+					}
+				}
+			if(tail->next == 0)
+				mk(tail->s);
+			else {
+				head = newword("command line arguments");
+				addrules(head, tail, strdup(""), VIR, mkinline, 0);
+				mk(head->s);
+			}
+		}
+	}
+	if(uflag)
+		prusage();
+	exits(0);
+}
+
+void
+badusage(void)
+{
+
+	fprint(2, "Usage: mk [-f file] [-n] [-a] [-e] [-t] [-k] [-i] [-d[egp]] [targets ...]\n");
+	Exit();
+}
+
+void *
+Malloc(int n)
+{
+	register void *s;
+
+	s = malloc(n);
+	if(!s) {
+		fprint(2, "mk: cannot alloc %d bytes\n", n);
+		Exit();
+	}
+	return(s);
+}
+
+void *
+Realloc(void *s, int n)
+{
+	if(s)
+		s = realloc(s, n);
+	else
+		s = malloc(n);
+	if(!s) {
+		fprint(2, "mk: cannot alloc %d bytes\n", n);
+		Exit();
+	}
+	return(s);
+}
+
+void
+regerror(char *s)
+{
+	if(patrule)
+		fprint(2, "mk: %s:%d: regular expression error; %s\n",
+			patrule->file, patrule->line, s);
+	else
+		fprint(2, "mk: %s:%d: regular expression error; %s\n",
+			infile, mkinline, s);
+	Exit();
+}
diff --git a/sys/src/cmd/mk/match.c b/sys/src/cmd/mk/match.c
new file mode 100755
index 000000000..f7d0cbf4e
--- /dev/null
+++ b/sys/src/cmd/mk/match.c
@@ -0,0 +1,54 @@
+#include	"mk.h"
+
+int
+match(char *name, char *template, char *stem)
+{
+	Rune r;
+	int n;
+
+	while(*name && *template){
+		n = chartorune(&r, template);
+		if (PERCENT(r))
+			break;
+		while (n--)
+			if(*name++ != *template++)
+				return 0;
+	}
+	if(!PERCENT(*template))
+		return 0;
+	n = strlen(name)-strlen(template+1);
+	if (n < 0)
+		return 0;
+	if (strcmp(template+1, name+n))
+		return 0;
+	strncpy(stem, name, n);
+	stem[n] = 0;
+	if(*template == '&')
+		return !charin(stem, "./");
+	return 1;
+}
+
+void
+subst(char *stem, char *template, char *dest, int dlen)
+{
+	Rune r;
+	char *s, *e;
+	int n;
+
+	e = dest+dlen-1;
+	while(*template){
+		n = chartorune(&r, template);
+		if (PERCENT(r)) {
+			template += n;
+			for (s = stem; *s; s++)
+				if(dest < e)
+					*dest++ = *s;
+		} else
+			while (n--){
+				if(dest < e)
+					*dest++ = *template;
+				template++;
+			}
+	}
+	*dest = 0;
+}
diff --git a/sys/src/cmd/mk/mk.c b/sys/src/cmd/mk/mk.c
new file mode 100755
index 000000000..a7a95a510
--- /dev/null
+++ b/sys/src/cmd/mk/mk.c
@@ -0,0 +1,236 @@
+#include	"mk.h"
+
+int runerrs;
+
+void
+mk(char *target)
+{
+	Node *node;
+	int did = 0;
+
+	nproc();		/* it can be updated dynamically */
+	nrep();			/* it can be updated dynamically */
+	runerrs = 0;
+	node = graph(target);
+	if(DEBUG(D_GRAPH)){
+		dumpn("new target\n", node);
+		Bflush(&bout);
+	}
+	clrmade(node);
+	while(node->flags&NOTMADE){
+		if(work(node, (Node *)0, (Arc *)0))
+			did = 1;	/* found something to do */
+		else {
+			if(waitup(1, (int *)0) > 0){
+				if(node->flags&(NOTMADE|BEINGMADE)){
+					assert(/*must be run errors*/ runerrs);
+					break;	/* nothing more waiting */
+				}
+			}
+		}
+	}
+	if(node->flags&BEINGMADE)
+		waitup(-1, (int *)0);
+	while(jobs)
+		waitup(-2, (int *)0);
+	assert(/*target didnt get done*/ runerrs || (node->flags&MADE));
+	if(did == 0)
+		Bprint(&bout, "mk: '%s' is up to date\n", node->name);
+}
+
+void
+clrmade(Node *n)
+{
+	Arc *a;
+
+	n->flags &= ~(CANPRETEND|PRETENDING);
+	if(strchr(n->name, '(') ==0 || n->time)
+		n->flags |= CANPRETEND;
+	MADESET(n, NOTMADE);
+	for(a = n->prereqs; a; a = a->next)
+		if(a->n)
+			clrmade(a->n);
+}
+
+static void
+unpretend(Node *n)
+{
+	MADESET(n, NOTMADE);
+	n->flags &= ~(CANPRETEND|PRETENDING);
+	n->time = 0;
+}
+
+int
+work(Node *node, Node *p, Arc *parc)
+{
+	Arc *a, *ra;
+	int weoutofdate;
+	int ready;
+	int did = 0;
+	char cwd[256];
+
+	/*print("work(%s) flags=0x%x time=%ld\n", node->name, node->flags, node->time);/**/
+	if(node->flags&BEINGMADE)
+		return(did);
+	if((node->flags&MADE) && (node->flags&PRETENDING) && p && outofdate(p, parc, 0)){
+		if(explain)
+			fprint(1, "unpretending %s(%ld) because %s is out of date(%ld)\n",
+				node->name, node->time, p->name, p->time);
+		unpretend(node);
+	}
+	/*
+		have a look if we are pretending in case
+		someone has been unpretended out from underneath us
+	*/
+	if(node->flags&MADE){
+		if(node->flags&PRETENDING){
+			node->time = 0;
+		}else
+			return(did);
+	}
+	/* consider no prerequisite case */
+	if(node->prereqs == 0){
+		if(node->time == 0){
+			if(getwd(cwd, sizeof cwd))
+				fprint(2, "mk: don't know how to make '%s' in directory %s\n", node->name, cwd);
+			else
+				fprint(2, "mk: don't know how to make '%s'\n", node->name);
+			if(kflag){
+				node->flags |= BEINGMADE;
+				runerrs++;
+			} else
+				Exit();
+		} else
+			MADESET(node, MADE);
+		return(did);
+	}
+	/*
+		now see if we are out of date or what
+	*/
+	ready = 1;
+	weoutofdate = aflag;
+	ra = 0;
+	for(a = node->prereqs; a; a = a->next)
+		if(a->n){
+			did = work(a->n, node, a) || did;
+			if(a->n->flags&(NOTMADE|BEINGMADE))
+				ready = 0;
+			if(outofdate(node, a, 0)){
+				weoutofdate = 1;
+				if((ra == 0) || (ra->n == 0)
+						|| (ra->n->time < a->n->time))
+					ra = a;
+			}
+		} else {
+			if(node->time == 0){
+				if(ra == 0)
+					ra = a;
+				weoutofdate = 1;
+			}
+		}
+	if(ready == 0)	/* can't do anything now */
+		return(did);
+	if(weoutofdate == 0){
+		MADESET(node, MADE);
+		return(did);
+	}
+	/*
+		can we pretend to be made?
+	*/
+	if((iflag == 0) && (node->time == 0) && (node->flags&(PRETENDING|CANPRETEND))
+			&& p && ra->n && !outofdate(p, ra, 0)){
+		node->flags &= ~CANPRETEND;
+		MADESET(node, MADE);
+		if(explain && ((node->flags&PRETENDING) == 0))
+			fprint(1, "pretending %s has time %ld\n", node->name, node->time);
+		node->flags |= PRETENDING;
+		return(did);
+	}
+	/*
+		node is out of date and we REALLY do have to do something.
+		quickly rescan for pretenders
+	*/
+	for(a = node->prereqs; a; a = a->next)
+		if(a->n && (a->n->flags&PRETENDING)){
+			if(explain)
+				Bprint(&bout, "unpretending %s because of %s because of %s\n",
+				a->n->name, node->name, ra->n? ra->n->name : "rule with no prerequisites");
+
+			unpretend(a->n);
+			did = work(a->n, node, a) || did;
+			ready = 0;
+		}
+	if(ready == 0)	/* try later unless nothing has happened for -k's sake */
+		return(did || work(node, p, parc));
+	did = dorecipe(node) || did;
+	return(did);
+}
+
+void
+update(int fake, Node *node)
+{
+	Arc *a;
+
+	MADESET(node, fake? BEINGMADE : MADE);
+	if(((node->flags&VIRTUAL) == 0) && (access(node->name, 0) == 0)){
+		node->time = timeof(node->name, 1);
+		node->flags &= ~(CANPRETEND|PRETENDING);
+		for(a = node->prereqs; a; a = a->next)
+			if(a->prog)
+				outofdate(node, a, 1);
+	} else {
+		node->time = 1;
+		for(a = node->prereqs; a; a = a->next)
+			if(a->n && outofdate(node, a, 1))
+				node->time = a->n->time;
+	}
+/*	print("----node %s time=%ld flags=0x%x\n", node->name, node->time, node->flags);/**/
+}
+
+static
+pcmp(char *prog, char *p, char *q)
+{
+	char buf[3*NAMEBLOCK];
+	int pid;
+
+	Bflush(&bout);
+	snprint(buf, sizeof buf, "%s '%s' '%s'\n", prog, p, q);
+	pid = pipecmd(buf, 0, 0);
+	while(waitup(-3, &pid) >= 0)
+		;
+	return(pid? 2:1);
+}
+
+int
+outofdate(Node *node, Arc *arc, int eval)
+{
+	char buf[3*NAMEBLOCK], *str;
+	Symtab *sym;
+	int ret;
+
+	str = 0;
+	if(arc->prog){
+		snprint(buf, sizeof buf, "%s%c%s", node->name, 0377,
+			arc->n->name);
+		sym = symlook(buf, S_OUTOFDATE, 0);
+		if(sym == 0 || eval){
+			if(sym == 0)
+				str = strdup(buf);
+			ret = pcmp(arc->prog, node->name, arc->n->name);
+			if(sym)
+				sym->u.value = ret;
+			else
+				symlook(str, S_OUTOFDATE, (void *)ret);
+		} else
+			ret = sym->u.value;
+		return(ret-1);
+	} else if(strchr(arc->n->name, '(') && arc->n->time == 0)  /* missing archive member */
+		return 1;
+	else
+		/*
+		 * Treat equal times as out-of-date.
+		 * It's a race, and the safer option is to do
+		 * extra building rather than not enough.
+	 	 */
+		return node->time <= arc->n->time;
+}
diff --git a/sys/src/cmd/mk/mk.h b/sys/src/cmd/mk/mk.h
new file mode 100755
index 000000000..fd48e71de
--- /dev/null
+++ b/sys/src/cmd/mk/mk.h
@@ -0,0 +1,174 @@
+#include	<u.h>
+#include	<libc.h>
+#include	<bio.h>
+#include	<regexp.h>
+
+extern Biobuf bout;
+
+typedef struct Bufblock
+{
+	struct Bufblock *next;
+	char 		*start;
+	char 		*end;
+	char 		*current;
+} Bufblock;
+
+typedef struct Word
+{
+	char 		*s;
+	struct Word 	*next;
+} Word;
+
+typedef struct Envy
+{
+	char 		*name;
+	Word 		*values;
+} Envy;
+
+extern Envy *envy;
+
+typedef struct Rule
+{
+	char 		*target;	/* one target */
+	Word 		*tail;		/* constituents of targets */
+	char 		*recipe;	/* do it ! */
+	short 		attr;		/* attributes */
+	short 		line;		/* source line */
+	char 		*file;		/* source file */
+	Word 		*alltargets;	/* all the targets */
+	int 		rule;		/* rule number */
+	Reprog		*pat;		/* reg exp goo */
+	char		*prog;		/* to use in out of date */
+	struct Rule	*chain;		/* hashed per target */
+	struct Rule	*next;
+} Rule;
+
+extern Rule *rules, *metarules, *patrule;
+
+/*	Rule.attr	*/
+#define		META		0x0001
+#define		UNUSED		0x0002
+#define		UPD		0x0004
+#define		QUIET		0x0008
+#define		VIR		0x0010
+#define		REGEXP		0x0020
+#define		NOREC		0x0040
+#define		DEL		0x0080
+#define		NOVIRT		0x0100
+
+#define		NREGEXP		10
+
+typedef struct Arc
+{
+	short		flag;
+	struct Node	*n;
+	Rule		*r;
+	char		*stem;
+	char		*prog;
+	char		*match[NREGEXP];
+	struct Arc	*next;
+} Arc;
+
+	/* Arc.flag */
+#define		TOGO		1
+
+typedef struct Node
+{
+	char		*name;
+	long		time;
+	unsigned short	flags;
+	Arc		*prereqs;
+	struct Node	*next;		/* list for a rule */
+} Node;
+
+	/* Node.flags */
+#define		VIRTUAL		0x0001
+#define		CYCLE		0x0002
+#define		READY		0x0004
+#define		CANPRETEND	0x0008
+#define		PRETENDING	0x0010
+#define		NOTMADE		0x0020
+#define		BEINGMADE	0x0040
+#define		MADE		0x0080
+#define		MADESET(n,m)	n->flags = (n->flags&~(NOTMADE|BEINGMADE|MADE))|(m)
+#define		PROBABLE	0x0100
+#define		VACUOUS		0x0200
+#define		NORECIPE	0x0400
+#define		DELETE		0x0800
+#define		NOMINUSE	0x1000
+
+typedef struct Job
+{
+	Rule		*r;	/* master rule for job */
+	Node		*n;	/* list of node targets */
+	char		*stem;
+	char		**match;
+	Word		*p;	/* prerequistes */
+	Word		*np;	/* new prerequistes */
+	Word		*t;	/* targets */
+	Word		*at;	/* all targets */
+	int		nproc;	/* slot number */
+	struct Job	*next;
+} Job;
+extern Job *jobs;
+
+typedef struct Symtab
+{
+	short		space;
+	char		*name;
+	union{
+		void		*ptr;
+		uintptr	value;
+	} u;
+	struct Symtab	*next;
+} Symtab;
+
+enum {
+	S_VAR,		/* variable -> value */
+	S_TARGET,	/* target -> rule */
+	S_TIME,		/* file -> time */
+	S_PID,		/* pid -> products */
+	S_NODE,		/* target name -> node */
+	S_AGG,		/* aggregate -> time */
+	S_BITCH,	/* bitched about aggregate not there */
+	S_NOEXPORT,	/* var -> noexport */
+	S_OVERRIDE,	/* can't override */
+	S_OUTOFDATE,	/* n1\377n2 -> 2(outofdate) or 1(not outofdate) */
+	S_MAKEFILE,	/* target -> node */
+	S_MAKEVAR,	/* dumpable mk variable */
+	S_EXPORTED,	/* var -> current exported value */
+	S_BULKED,	/* we have bulked this dir */
+	S_WESET,	/* variable; we set in the mkfile */
+	S_INTERNAL,	/* an internal mk variable (e.g., stem, target) */
+};
+
+extern	int	debug;
+extern	int	nflag, tflag, iflag, kflag, aflag, mflag;
+extern	int	mkinline;
+extern	char	*infile;
+extern	int	nreps;
+extern	char	*explain;
+extern	char	*termchars;
+extern	char 	*shell;
+extern	char 	*shellname;
+extern	char 	*shflags;
+extern	int	IWS;
+
+#define	SYNERR(l)	(fprint(2, "mk: %s:%d: syntax error; ", infile, ((l)>=0)?(l):mkinline))
+#define	RERR(r)		(fprint(2, "mk: %s:%d: rule error; ", (r)->file, (r)->line))
+#define	NAMEBLOCK	1000
+#define	BIGBLOCK	20000
+
+#define	SEP(c)		(((c)==' ')||((c)=='\t')||((c)=='\n'))
+#define WORDCHR(r)	((r) > ' ' && !utfrune("!\"#$%&'()*+,-./:;<=>?@[\\]^`{|}~", (r)))
+
+#define	DEBUG(x)	(debug&(x))
+#define		D_PARSE		0x01
+#define		D_GRAPH		0x02
+#define		D_EXEC		0x04
+
+#define	LSEEK(f,o,p)	seek(f,o,p)
+
+#define	PERCENT(ch)	(((ch) == '%') || ((ch) == '&'))
+
+#include	"fns.h"
diff --git a/sys/src/cmd/mk/mkconv b/sys/src/cmd/mk/mkconv
new file mode 100755
index 000000000..fc1466578
--- /dev/null
+++ b/sys/src/cmd/mk/mkconv
@@ -0,0 +1,30 @@
+#!/bin/rc
+
+x=/tmp/mk$pid
+
+fn sigexit { rm -f $x }
+fn sigint { rm -f $x }
+
+tee $x < $1 | sed -e 's/\$\(([^)]*)\)([        :\/])/$\1\2/g
+	s/\$\(([^)]*)\)$/$\1/g
+	s/\$\(([^)]*)\)/${\1}/g
+	s/^     @/  /
+	/^	-/,/[^\\]$/{
+		/[^\\]\$/s/$/; set -e/
+	}
+	/^	-/s/	-/	set +e; /
+	s/:\&/:/
+	s/\$% /$stem /g
+	s/\$%\./$stem\./g
+	s/\$%/${stem}/g
+	s/\$@([ 	]|$)/$target\1/g
+	s/\$@/${target}/g
+	s/\$\^/${prereq}/g
+	s/\$\?/$newprereq/g'
+
+if(grep -s 'cd[ 	]|make' < $x){
+	{
+		echo 'Warning: recipes containing cd or make need attention.'
+		grep 'cd[ 	]|make' < $x
+	} >[1=2]
+}
diff --git a/sys/src/cmd/mk/mkfile b/sys/src/cmd/mk/mkfile
new file mode 100755
index 000000000..ac7de276e
--- /dev/null
+++ b/sys/src/cmd/mk/mkfile
@@ -0,0 +1,38 @@
+</$objtype/mkfile
+
+TARG=mk
+OFILES=arc.$O\
+	archive.$O\
+	bufblock.$O\
+	env.$O\
+	file.$O\
+	graph.$O\
+	job.$O\
+	lex.$O\
+	main.$O\
+	match.$O\
+	mk.$O\
+	parse.$O\
+	rc.$O\
+	recipe.$O\
+	rule.$O\
+	run.$O\
+	shprint.$O\
+	symtab.$O\
+	var.$O\
+	varsub.$O\
+	word.$O\
+	plan9.$O\
+
+HFILES=fns.h\
+	mk.h\
+
+BIN=/$objtype/bin
+
+UPDATE=\
+	mkfile\
+	$HFILES\
+	${OFILES:%.$O=%.c}\
+
+</sys/src/cmd/mkone
+
diff --git a/sys/src/cmd/mk/parse.c b/sys/src/cmd/mk/parse.c
new file mode 100755
index 000000000..ac3f01faf
--- /dev/null
+++ b/sys/src/cmd/mk/parse.c
@@ -0,0 +1,309 @@
+#include	"mk.h"
+
+char *infile;
+int mkinline;
+static int rhead(char *, Word **, Word **, int *, char **);
+static char *rbody(Biobuf*);
+extern Word *target1;
+
+void
+parse(char *f, int fd, int varoverride)
+{
+	int hline;
+	char *body;
+	Word *head, *tail;
+	int attr, set, pid;
+	char *prog, *p;
+	int newfd;
+	Biobuf in;
+	Bufblock *buf;
+
+	if(fd < 0){
+		perror(f);
+		Exit();
+	}
+	ipush();
+	infile = strdup(f);
+	mkinline = 1;
+	Binit(&in, fd, OREAD);
+	buf = newbuf();
+	while(assline(&in, buf)){
+		hline = mkinline;
+		switch(rhead(buf->start, &head, &tail, &attr, &prog))
+		{
+		case '<':
+			p = wtos(tail, ' ');
+			if(*p == 0){
+				SYNERR(-1);
+				fprint(2, "missing include file name\n");
+				Exit();
+			}
+			newfd = open(p, OREAD);
+			if(newfd < 0){
+				fprint(2, "warning: skipping missing include file: ");
+				perror(p);
+			} else
+				parse(p, newfd, 0);
+			break;
+		case '|':
+			p = wtos(tail, ' ');
+			if(*p == 0){
+				SYNERR(-1);
+				fprint(2, "missing include program name\n");
+				Exit();
+			}
+			execinit();
+			pid=pipecmd(p, envy, &newfd);
+			if(newfd < 0){
+				fprint(2, "warning: skipping missing program file: ");
+				perror(p);
+			} else
+				parse(p, newfd, 0);
+			while(waitup(-3, &pid) >= 0)
+				;
+			if(pid != 0){
+				fprint(2, "bad include program status\n");
+				Exit();
+			}
+			break;
+		case ':':
+			body = rbody(&in);
+			addrules(head, tail, body, attr, hline, prog);
+			break;
+		case '=':
+			if(head->next){
+				SYNERR(-1);
+				fprint(2, "multiple vars on left side of assignment\n");
+				Exit();
+			}
+			if(symlook(head->s, S_OVERRIDE, 0)){
+				set = varoverride;
+			} else {
+				set = 1;
+				if(varoverride)
+					symlook(head->s, S_OVERRIDE, (void *)"");
+			}
+			if(set){
+/*
+char *cp;
+dumpw("tail", tail);
+cp = wtos(tail, ' '); print("assign %s to %s\n", head->s, cp); free(cp);
+*/
+				setvar(head->s, (void *) tail);
+				symlook(head->s, S_WESET, (void *)"");
+			}
+			if(attr)
+				symlook(head->s, S_NOEXPORT, (void *)"");
+			break;
+		default:
+			SYNERR(hline);
+			fprint(2, "expected one of :<=\n");
+			Exit();
+			break;
+		}
+	}
+	close(fd);
+	freebuf(buf);
+	ipop();
+}
+
+void
+addrules(Word *head, Word *tail, char *body, int attr, int hline, char *prog)
+{
+	Word *w;
+
+	assert(/*addrules args*/ head && body);
+		/* tuck away first non-meta rule as default target*/
+	if(target1 == 0 && !(attr&REGEXP)){
+		for(w = head; w; w = w->next)
+			if(charin(w->s, "%&"))
+				break;
+		if(w == 0)
+			target1 = wdup(head);
+	}
+	for(w = head; w; w = w->next)
+		addrule(w->s, tail, body, head, attr, hline, prog);
+}
+
+static int
+rhead(char *line, Word **h, Word **t, int *attr, char **prog)
+{
+	char *p;
+	char *pp;
+	int sep;
+	Rune r;
+	int n;
+	Word *w;
+
+	p = charin(line,":=<");
+	if(p == 0)
+		return('?');
+	sep = *p;
+	*p++ = 0;
+	if(sep == '<' && *p == '|'){
+		sep = '|';
+		p++;
+	}
+	*attr = 0;
+	*prog = 0;
+	if(sep == '='){
+		pp = charin(p, termchars);	/* termchars is shell-dependent */
+		if (pp && *pp == '=') {
+			while (p != pp) {
+				n = chartorune(&r, p);
+				switch(r)
+				{
+				default:
+					SYNERR(-1);
+					fprint(2, "unknown attribute '%c'\n",*p);
+					Exit();
+				case 'U':
+					*attr = 1;
+					break;
+				}
+				p += n;
+			}
+			p++;		/* skip trailing '=' */
+		}
+	}
+	if((sep == ':') && *p && (*p != ' ') && (*p != '\t')){
+		while (*p) {
+			n = chartorune(&r, p);
+			if (r == ':')
+				break;
+			p += n;
+			switch(r)
+			{
+			default:
+				SYNERR(-1);
+				fprint(2, "unknown attribute '%c'\n", p[-1]);
+				Exit();
+			case 'D':
+				*attr |= DEL;
+				break;
+			case 'E':
+				*attr |= NOMINUSE;
+				break;
+			case 'n':
+				*attr |= NOVIRT;
+				break;
+			case 'N':
+				*attr |= NOREC;
+				break;
+			case 'P':
+				pp = utfrune(p, ':');
+				if (pp == 0 || *pp == 0)
+					goto eos;
+				*pp = 0;
+				*prog = strdup(p);
+				*pp = ':';
+				p = pp;
+				break;
+			case 'Q':
+				*attr |= QUIET;
+				break;
+			case 'R':
+				*attr |= REGEXP;
+				break;
+			case 'U':
+				*attr |= UPD;
+				break;
+			case 'V':
+				*attr |= VIR;
+				break;
+			}
+		}
+		if (*p++ != ':') {
+	eos:
+			SYNERR(-1);
+			fprint(2, "missing trailing :\n");
+			Exit();
+		}
+	}
+	*h = w = stow(line);
+	if(*w->s == 0 && sep != '<' && sep != '|') {
+		SYNERR(mkinline-1);
+		fprint(2, "no var on left side of assignment/rule\n");
+		Exit();
+	}
+	*t = stow(p);
+	return(sep);
+}
+
+static char *
+rbody(Biobuf *in)
+{
+	Bufblock *buf;
+	int r, lastr;
+	char *p;
+
+	lastr = '\n';
+	buf = newbuf();
+	for(;;){
+		r = Bgetrune(in);
+		if (r < 0)
+			break;
+		if (lastr == '\n') {
+			if (r == '#')
+				rinsert(buf, r);
+			else if (r != ' ' && r != '\t') {
+				Bungetrune(in);
+				break;
+			}
+		} else
+			rinsert(buf, r);
+		lastr = r;
+		if (r == '\n')
+			mkinline++;
+	}
+	insert(buf, 0);
+	p = strdup(buf->start);
+	freebuf(buf);
+	return p;
+}
+
+struct input
+{
+	char *file;
+	int line;
+	struct input *next;
+};
+static struct input *inputs = 0;
+
+void
+ipush(void)
+{
+	struct input *in, *me;
+
+	me = (struct input *)Malloc(sizeof(*me));
+	me->file = infile;
+	me->line = mkinline;
+	me->next = 0;
+	if(inputs == 0)
+		inputs = me;
+	else {
+		for(in = inputs; in->next; )
+			in = in->next;
+		in->next = me;
+	}
+}
+
+void
+ipop(void)
+{
+	struct input *in, *me;
+
+	assert(/*pop input list*/ inputs != 0);
+	if(inputs->next == 0){
+		me = inputs;
+		inputs = 0;
+	} else {
+		for(in = inputs; in->next->next; )
+			in = in->next;
+		me = in->next;
+		in->next = 0;
+	}
+	infile = me->file;
+	mkinline = me->line;
+	free((char *)me);
+}
diff --git a/sys/src/cmd/mk/plan9.c b/sys/src/cmd/mk/plan9.c
new file mode 100755
index 000000000..d87fcfa4d
--- /dev/null
+++ b/sys/src/cmd/mk/plan9.c
@@ -0,0 +1,437 @@
+#include	"mk.h"
+
+char 	*shell =	"/bin/rc";
+char 	*shellname =	"rc";
+
+static	Word	*encodenulls(char*, int);
+
+void
+readenv(void)
+{
+	char *p;
+	int envf, f;
+	Dir *e;
+	char nam[1024];
+	int i, n, len;
+	Word *w;
+
+	rfork(RFENVG);	/*  use copy of the current environment variables */
+
+	envf = open("/env", OREAD);
+	if(envf < 0)
+		return;
+	while((n = dirread(envf, &e)) > 0){
+		for(i = 0; i < n; i++){
+			len = e[i].length;
+				/* don't import funny names, NULL values,
+				 * or internal mk variables
+				 */
+			if(len <= 0 || *shname(e[i].name) != '\0')
+				continue;
+			if (symlook(e[i].name, S_INTERNAL, 0))
+				continue;
+			snprint(nam, sizeof nam, "/env/%s", e[i].name);
+			f = open(nam, OREAD);
+			if(f < 0)
+				continue;
+			p = Malloc(len+1);
+			if(read(f, p, len) != len){
+				perror(nam);
+				close(f);
+				continue;
+			}
+			close(f);
+			if (p[len-1] == 0)
+				len--;
+			else
+				p[len] = 0;
+			w = encodenulls(p, len);
+			free(p);
+			p = strdup(e[i].name);
+			setvar(p, (void *) w);
+			symlook(p, S_EXPORTED, (void*)"")->u.ptr = "";
+		}
+		free(e);
+	}
+	close(envf);
+}
+
+/* break string of values into words at 01's or nulls*/
+static Word *
+encodenulls(char *s, int n)
+{
+	Word *w, *head;
+	char *cp;
+
+	head = w = 0;
+	while (n-- > 0) {
+		for (cp = s; *cp && *cp != '\0'; cp++)
+				n--;
+		*cp = 0;
+		if (w) {
+			w->next = newword(s);
+			w = w->next;
+		} else
+			head = w = newword(s);
+		s = cp+1;
+	}
+	if (!head)
+		head = newword("");
+	return head;
+}
+
+/* as well as 01's, change blanks to nulls, so that rc will
+ * treat the words as separate arguments
+ */
+void
+exportenv(Envy *e)
+{
+	int f, n, hasvalue, first;
+	Word *w;
+	Symtab *sy;
+	char nam[256];
+
+	for(;e->name; e++){
+		sy = symlook(e->name, S_VAR, 0);
+		if (e->values == 0 || e->values->s == 0 || e->values->s[0] == 0)
+			hasvalue = 0;
+		else
+			hasvalue = 1;
+		if(sy == 0 && !hasvalue)	/* non-existant null symbol */
+			continue;
+		snprint(nam, sizeof nam, "/env/%s", e->name);
+		if (sy != 0 && !hasvalue) {	/* Remove from environment */
+				/* we could remove it from the symbol table
+				 * too, but we're in the child copy, and it
+				 * would still remain in the parent's table.
+				 */
+			remove(nam);
+			delword(e->values);
+			e->values = 0;		/* memory leak */
+			continue;
+		}
+	
+		f = create(nam, OWRITE, 0666L);
+		if(f < 0) {
+			fprint(2, "can't create %s, f=%d\n", nam, f);
+			perror(nam);
+			continue;
+		}
+		first = 1;
+		for (w = e->values; w; w = w->next) {
+			n = strlen(w->s);
+			if (n) {
+				if(first)
+					first = 0;
+				else{
+					if (write (f, "\0", 1) != 1)
+						perror(nam);
+				}
+				if (write(f, w->s, n) != n)
+					perror(nam);
+			}
+		}
+		close(f);
+	}
+}
+
+int
+waitfor(char *msg)
+{
+	Waitmsg *w;
+	int pid;
+
+	if((w=wait()) == nil)
+		return -1;
+	strecpy(msg, msg+ERRMAX, w->msg);
+	pid = w->pid;
+	free(w);
+	return pid;
+}
+
+void
+expunge(int pid, char *msg)
+{
+	postnote(PNPROC, pid, msg);
+}
+
+int
+execsh(char *args, char *cmd, Bufblock *buf, Envy *e)
+{
+	char *p;
+	int tot, n, pid, in[2], out[2];
+
+	if(buf && pipe(out) < 0){
+		perror("pipe");
+		Exit();
+	}
+	pid = rfork(RFPROC|RFFDG|RFENVG);
+	if(pid < 0){
+		perror("mk rfork");
+		Exit();
+	}
+	if(pid == 0){
+		if(buf)
+			close(out[0]);
+		if(pipe(in) < 0){
+			perror("pipe");
+			Exit();
+		}
+		pid = fork();
+		if(pid < 0){
+			perror("mk fork");
+			Exit();
+		}
+		if(pid != 0){
+			dup(in[0], 0);
+			if(buf){
+				dup(out[1], 1);
+				close(out[1]);
+			}
+			close(in[0]);
+			close(in[1]);
+			if (e)
+				exportenv(e);
+			if(shflags)
+				execl(shell, shellname, shflags, args, nil);
+			else
+				execl(shell, shellname, args, nil);
+			perror(shell);
+			_exits("exec");
+		}
+		close(out[1]);
+		close(in[0]);
+		p = cmd+strlen(cmd);
+		while(cmd < p){
+			n = write(in[1], cmd, p-cmd);
+			if(n < 0)
+				break;
+			cmd += n;
+		}
+		close(in[1]);
+		_exits(0);
+	}
+	if(buf){
+		close(out[1]);
+		tot = 0;
+		for(;;){
+			if (buf->current >= buf->end)
+				growbuf(buf);
+			n = read(out[0], buf->current, buf->end-buf->current);
+			if(n <= 0)
+				break;
+			buf->current += n;
+			tot += n;
+		}
+		if (tot && buf->current[-1] == '\n')
+			buf->current--;
+		close(out[0]);
+	}
+	return pid;
+}
+
+int
+pipecmd(char *cmd, Envy *e, int *fd)
+{
+	int pid, pfd[2];
+
+	if(DEBUG(D_EXEC))
+		fprint(1, "pipecmd='%s'\n", cmd);/**/
+
+	if(fd && pipe(pfd) < 0){
+		perror("pipe");
+		Exit();
+	}
+	pid = rfork(RFPROC|RFFDG|RFENVG);
+	if(pid < 0){
+		perror("mk fork");
+		Exit();
+	}
+	if(pid == 0){
+		if(fd){
+			close(pfd[0]);
+			dup(pfd[1], 1);
+			close(pfd[1]);
+		}
+		if(e)
+			exportenv(e);
+		if(shflags)
+			execl(shell, shellname, shflags, "-c", cmd, nil);
+		else
+			execl(shell, shellname, "-c", cmd, nil);
+		perror(shell);
+		_exits("exec");
+	}
+	if(fd){
+		close(pfd[1]);
+		*fd = pfd[0];
+	}
+	return pid;
+}
+
+void
+Exit(void)
+{
+	while(waitpid() >= 0)
+		;
+	exits("error");
+}
+
+int
+notifyf(void *a, char *msg)
+{
+	static int nnote;
+
+	USED(a);
+	if(++nnote > 100){	/* until andrew fixes his program */
+		fprint(2, "mk: too many notes\n");
+		notify(0);
+		abort();
+	}
+	if(strcmp(msg, "interrupt")!=0 && strcmp(msg, "hangup")!=0)
+		return 0;
+	killchildren(msg);
+	return -1;
+}
+
+void
+catchnotes()
+{
+	atnotify(notifyf, 1);
+}
+
+char*
+maketmp(void)
+{
+	static char temp[] = "/tmp/mkargXXXXXX";
+
+	mktemp(temp);
+	return temp;
+}
+
+int
+chgtime(char *name)
+{
+	Dir sbuf;
+
+	if(access(name, AEXIST) >= 0) {
+		nulldir(&sbuf);
+		sbuf.mtime = time((long *)0);
+		return dirwstat(name, &sbuf);
+	}
+	return close(create(name, OWRITE, 0666));
+}
+
+void
+rcopy(char **to, Resub *match, int n)
+{
+	int c;
+	char *p;
+
+	*to = match->sp;		/* stem0 matches complete target */
+	for(to++, match++; --n > 0; to++, match++){
+		if(match->sp && match->ep){
+			p = match->ep;
+			c = *p;
+			*p = 0;
+			*to = strdup(match->sp);
+			*p = c;
+		}
+		else
+			*to = 0;
+	}
+}
+
+void
+dirtime(char *dir, char *path)
+{
+	int i, fd, n;
+	long mtime;
+	Dir *d;
+	char buf[4096];
+
+	fd = open(dir, OREAD);
+	if(fd >= 0){
+		while((n = dirread(fd, &d)) > 0){
+			for(i=0; i<n; i++){
+				mtime = d[i].mtime;
+				/* defensive driving: this does happen */
+				if(mtime == 0)
+					mtime = 1;
+				snprint(buf, sizeof buf, "%s%s", path,
+					d[i].name);
+				if(symlook(buf, S_TIME, 0) == nil)
+					symlook(strdup(buf), S_TIME,
+						(void*)mtime)->u.value = mtime;
+			}
+			free(d);
+		}
+		close(fd);
+	}
+}
+
+void
+bulkmtime(char *dir)
+{
+	char buf[4096];
+	char *ss, *s, *sym;
+
+	if(dir){
+		sym = dir;
+		s = dir;
+		if(strcmp(dir, "/") == 0)
+			strecpy(buf, buf + sizeof buf - 1, dir);
+		else
+			snprint(buf, sizeof buf, "%s/", dir);
+	}else{
+		s = ".";
+		sym = "";
+		buf[0] = 0;
+	}
+	if(symlook(sym, S_BULKED, 0))
+		return;
+	ss = strdup(sym);
+	symlook(ss, S_BULKED, (void*)ss);
+	dirtime(s, buf);
+}
+
+ulong
+mkmtime(char *name, int force)
+{
+	Dir *d;
+	char *s, *ss, carry;
+	ulong t;
+	Symtab *sym;
+	char buf[4096];
+
+	strecpy(buf, buf + sizeof buf - 1, name);
+	cleanname(buf);
+	name = buf;
+
+	s = utfrrune(name, '/');
+	if(s == name)
+		s++;
+	if(s){
+		ss = name;
+		carry = *s;
+		*s = 0;
+	}else{
+		ss = 0;
+		carry = 0;
+	}
+	bulkmtime(ss);
+	if(carry)
+		*s = carry;
+	if(!force){
+		sym = symlook(name, S_TIME, 0);
+		if(sym)
+			return sym->u.value;
+		return 0;
+	}
+	if((d = dirstat(name)) == nil)
+		return 0;
+	t = d->mtime;
+	free(d);
+	return t;
+}
+
diff --git a/sys/src/cmd/mk/rc.c b/sys/src/cmd/mk/rc.c
new file mode 100755
index 000000000..657ddf278
--- /dev/null
+++ b/sys/src/cmd/mk/rc.c
@@ -0,0 +1,175 @@
+#include	"mk.h"
+
+char	*termchars = "'= \t";	/*used in parse.c to isolate assignment attribute*/
+char	*shflags = "-I";	/* rc flag to force non-interactive mode */
+int	IWS = '\1';		/* inter-word separator in env - not used in plan 9 */
+
+/*
+ *	This file contains functions that depend on rc's syntax.  Most
+ *	of the routines extract strings observing rc's escape conventions
+ */
+
+
+/*
+ *	skip a token in single quotes.
+ */
+static char *
+squote(char *cp)
+{
+	Rune r;
+	int n;
+
+	while(*cp){
+		n = chartorune(&r, cp);
+		if(r == '\'') {
+			n += chartorune(&r, cp+n);
+			if(r != '\'')
+				return(cp);
+		}
+		cp += n;
+	}
+	SYNERR(-1);		/* should never occur */
+	fprint(2, "missing closing '\n");
+	return 0;
+}
+
+/*
+ *	search a string for characters in a pattern set
+ *	characters in quotes and variable generators are escaped
+ */
+char *
+charin(char *cp, char *pat)
+{
+	Rune r;
+	int n, vargen;
+
+	vargen = 0;
+	while(*cp){
+		n = chartorune(&r, cp);
+		switch(r){
+		case '\'':			/* skip quoted string */
+			cp = squote(cp+1);	/* n must = 1 */
+			if(!cp)
+				return 0;
+			break;
+		case '$':
+			if(*(cp+1) == '{')
+				vargen = 1;
+			break;
+		case '}':
+			if(vargen)
+				vargen = 0;
+			else if(utfrune(pat, r))
+				return cp;
+			break;
+		default:
+			if(vargen == 0 && utfrune(pat, r))
+				return cp;
+			break;
+		}
+		cp += n;
+	}
+	if(vargen){
+		SYNERR(-1);
+		fprint(2, "missing closing } in pattern generator\n");
+	}
+	return 0;
+}
+
+/*
+ *	extract an escaped token.  Possible escape chars are single-quote,
+ *	double-quote,and backslash.  Only the first is valid for rc. the
+ *	others are just inserted into the receiving buffer.
+ */
+char*
+expandquote(char *s, Rune r, Bufblock *b)
+{
+	if (r != '\'') {
+		rinsert(b, r);
+		return s;
+	}
+
+	while(*s){
+		s += chartorune(&r, s);
+		if(r == '\'') {
+			if(*s == '\'')
+				s++;
+			else
+				return s;
+		}
+		rinsert(b, r);
+	}
+	return 0;
+}
+
+/*
+ *	Input an escaped token.  Possible escape chars are single-quote,
+ *	double-quote and backslash.  Only the first is a valid escape for
+ *	rc; the others are just inserted into the receiving buffer.
+ */
+int
+escapetoken(Biobuf *bp, Bufblock *buf, int preserve, int esc)
+{
+	int c, line;
+
+	if(esc != '\'')
+		return 1;
+
+	line = mkinline;
+	while((c = nextrune(bp, 0)) > 0){
+		if(c == '\''){
+			if(preserve)
+				rinsert(buf, c);
+			c = Bgetrune(bp);
+			if (c < 0)
+				break;
+			if(c != '\''){
+				Bungetrune(bp);
+				return 1;
+			}
+		}
+		rinsert(buf, c);
+	}
+	SYNERR(line); fprint(2, "missing closing %c\n", esc);
+	return 0;
+}
+
+/*
+ *	copy a single-quoted string; s points to char after opening quote
+ */
+static char *
+copysingle(char *s, Bufblock *buf)
+{
+	Rune r;
+
+	while(*s){
+		s += chartorune(&r, s);
+		rinsert(buf, r);
+		if(r == '\'')
+			break;
+	}
+	return s;
+}
+/*
+ *	check for quoted strings.  backquotes are handled here; single quotes above.
+ *	s points to char after opening quote, q.
+ */
+char *
+copyq(char *s, Rune q, Bufblock *buf)
+{
+	if(q == '\'')				/* copy quoted string */
+		return copysingle(s, buf);
+
+	if(q != '`')				/* not quoted */
+		return s;
+
+	while(*s){				/* copy backquoted string */
+		s += chartorune(&q, s);
+		rinsert(buf, q);
+		if(q == '}')
+			break;
+		if(q == '\'')
+			s = copysingle(s, buf);	/* copy quoted string */
+	}
+	return s;
+}
diff --git a/sys/src/cmd/mk/recipe.c b/sys/src/cmd/mk/recipe.c
new file mode 100755
index 000000000..93a6f56f2
--- /dev/null
+++ b/sys/src/cmd/mk/recipe.c
@@ -0,0 +1,120 @@
+#include	"mk.h"
+
+int
+dorecipe(Node *node)
+{
+	int did = 0;
+	char buf[BIGBLOCK], cwd[256];
+	Arc *a, *aa;
+	Node *n;
+	Rule *r = 0;
+	Symtab *s;
+	Word head, ahead, lp, ln, *w, *ww, *aw;
+
+	aa = 0;
+	/*
+		pick up the rule
+	*/
+	for(a = node->prereqs; a; a = a->next)
+		if(*a->r->recipe)
+			r = (aa = a)->r;
+	/*
+		no recipe? go to buggery!
+	*/
+	if(r == 0){
+		if(!(node->flags&VIRTUAL) && !(node->flags&NORECIPE)){
+			if(getwd(cwd, sizeof cwd))
+				fprint(2, "mk: no recipe to make '%s' in directory %s\n", node->name, cwd);
+			else
+				fprint(2, "mk: no recipe to make '%s'\n", node->name);
+			Exit();
+		}
+		if(strchr(node->name, '(') && node->time == 0)
+			MADESET(node, MADE);
+		else
+			update(0, node);
+		if(tflag){
+			if(!(node->flags&VIRTUAL))
+				touch(node->name);
+			else if(explain)
+				Bprint(&bout, "no touch of virtual '%s'\n", node->name);
+		}
+		return(did);
+	}
+	/*
+		build the node list
+	*/
+	node->next = 0;
+	head.next = 0;
+	ww = &head;
+	ahead.next = 0;
+	aw = &ahead;
+	if(r->attr&REGEXP){
+		ww->next = newword(node->name);
+		aw->next = newword(node->name);
+	} else {
+		for(w = r->alltargets; w; w = w->next){
+			if(r->attr&META)
+				subst(aa->stem, w->s, buf, sizeof(buf));
+			else
+				strecpy(buf, buf + sizeof buf - 1, w->s);
+			aw->next = newword(buf);
+			aw = aw->next;
+			if((s = symlook(buf, S_NODE, 0)) == 0)
+				continue;	/* not a node we are interested in */
+			n = s->u.ptr;
+			if(aflag == 0 && n->time) {
+				for(a = n->prereqs; a; a = a->next)
+					if(a->n && outofdate(n, a, 0))
+						break;
+				if(a == 0)
+					continue;
+			}
+			ww->next = newword(buf);
+			ww = ww->next;
+			if(n == node) continue;
+			n->next = node->next;
+			node->next = n;
+		}
+	}
+	for(n = node; n; n = n->next)
+		if((n->flags&READY) == 0)
+			return(did);
+	/*
+		gather the params for the job
+	*/
+	lp.next = ln.next = 0;
+	for(n = node; n; n = n->next){
+		for(a = n->prereqs; a; a = a->next){
+			if(a->n){
+				addw(&lp, a->n->name);
+				if(outofdate(n, a, 0)){
+					addw(&ln, a->n->name);
+					if(explain)
+						fprint(1, "%s(%ld) < %s(%ld)\n",
+							n->name, n->time, a->n->name, a->n->time);
+				}
+			} else {
+				if(explain)
+					fprint(1, "%s has no prerequisites\n",
+							n->name);
+			}
+		}
+		MADESET(n, BEINGMADE);
+	}
+/*	print("lt=%s ln=%s lp=%s\n",wtos(head.next, ' '),wtos(ln.next, ' '),wtos(lp.next, ' '));/**/
+	run(newjob(r, node, aa->stem, aa->match, lp.next, ln.next, head.next, ahead.next));
+	return(1);
+}
+
+void
+addw(Word *w, char *s)
+{
+	Word *lw;
+
+	for(lw = w; w = w->next; lw = w){
+		if(strcmp(s, w->s) == 0)
+			return;
+	}
+	lw->next = newword(s);
+}
diff --git a/sys/src/cmd/mk/rule.c b/sys/src/cmd/mk/rule.c
new file mode 100755
index 000000000..8d4b493b7
--- /dev/null
+++ b/sys/src/cmd/mk/rule.c
@@ -0,0 +1,108 @@
+#include	"mk.h"
+
+static Rule *lr, *lmr;
+static rcmp(Rule *r, char *target, Word *tail);
+static int nrules = 0;
+
+void
+addrule(char *head, Word *tail, char *body, Word *ahead, int attr, int hline, char *prog)
+{
+	Rule *r;
+	Rule *rr;
+	Symtab *sym;
+	int reuse;
+
+	r = 0;
+	reuse = 0;
+	if(sym = symlook(head, S_TARGET, 0)){
+		for(r = sym->u.ptr; r; r = r->chain)
+			if(rcmp(r, head, tail) == 0){
+				reuse = 1;
+				break;
+			}
+	}
+	if(r == 0)
+		r = (Rule *)Malloc(sizeof(Rule));
+	r->target = head;
+	r->tail = tail;
+	r->recipe = body;
+	r->line = hline;
+	r->file = infile;
+	r->attr = attr;
+	r->alltargets = ahead;
+	r->prog = prog;
+	r->rule = nrules++;
+
+	if(!reuse){
+		rr = symlook(head, S_TARGET, r)->u.ptr;
+		if(rr != r){
+			r->chain = rr->chain;
+			rr->chain = r;
+		} else
+			r->chain = 0;
+	}
+	if(!reuse)
+		r->next = 0;
+	if((attr&REGEXP) || charin(head, "%&")){
+		r->attr |= META;
+		if(reuse)
+			return;
+		if(attr&REGEXP){
+			patrule = r;
+			r->pat = regcomp(head);
+		}
+		if(metarules == 0)
+			metarules = lmr = r;
+		else {
+			lmr->next = r;
+			lmr = r;
+		}
+	} else {
+		if(reuse)
+			return;
+		r->pat = 0;
+		if(rules == 0)
+			rules = lr = r;
+		else {
+			lr->next = r;
+			lr = r;
+		}
+	}
+}
+
+void
+dumpr(char *s, Rule *r)
+{
+	Bprint(&bout, "%s: start=%p\n", s, r);
+	for(; r; r = r->next){
+		Bprint(&bout, "\tRule %p: %s:%d attr=%x next=%p chain=%p alltarget='%s'",
+			r, r->file, r->line, r->attr, r->next, r->chain, wtos(r->alltargets, ' '));
+		if(r->prog)
+			Bprint(&bout, " prog='%s'", r->prog);
+		Bprint(&bout, "\n\ttarget=%s: %s\n", r->target, wtos(r->tail,' '));
+		Bprint(&bout, "\trecipe@%p='%s'\n", r->recipe, r->recipe);
+	}
+}
+
+static int
+rcmp(Rule *r, char *target, Word *tail)
+{
+	Word *w;
+
+	if(strcmp(r->target, target))
+		return 1;
+	for(w = r->tail; w && tail; w = w->next, tail = tail->next)
+		if(strcmp(w->s, tail->s))
+			return 1;
+	return(w || tail);
+}
+
+char *
+rulecnt(void)
+{
+	char *s;
+
+	s = Malloc(nrules);
+	memset(s, 0, nrules);
+	return(s);
+}
diff --git a/sys/src/cmd/mk/run.c b/sys/src/cmd/mk/run.c
new file mode 100755
index 000000000..c01b519fd
--- /dev/null
+++ b/sys/src/cmd/mk/run.c
@@ -0,0 +1,297 @@
+#include	"mk.h"
+
+typedef struct Event
+{
+	int pid;
+	Job *job;
+} Event;
+static Event *events;
+static int nevents, nrunning, nproclimit;
+
+typedef struct Process
+{
+	int pid;
+	int status;
+	struct Process *b, *f;
+} Process;
+static Process *phead, *pfree;
+static void sched(void);
+static void pnew(int, int), pdelete(Process *);
+
+int pidslot(int);
+
+void
+run(Job *j)
+{
+	Job *jj;
+
+	if(jobs){
+		for(jj = jobs; jj->next; jj = jj->next)
+			;
+		jj->next = j;
+	} else 
+		jobs = j;
+	j->next = 0;
+	/* this code also in waitup after parse redirect */
+	if(nrunning < nproclimit)
+		sched();
+}
+
+static void
+sched(void)
+{
+	char *flags;
+	Job *j;
+	Bufblock *buf;
+	int slot;
+	Node *n;
+	Envy *e;
+
+	if(jobs == 0){
+		usage();
+		return;
+	}
+	j = jobs;
+	jobs = j->next;
+	if(DEBUG(D_EXEC))
+		fprint(1, "firing up job for target %s\n", wtos(j->t, ' '));
+	slot = nextslot();
+	events[slot].job = j;
+	buf = newbuf();
+	e = buildenv(j, slot);
+	shprint(j->r->recipe, e, buf);
+	if(!tflag && (nflag || !(j->r->attr&QUIET)))
+		Bwrite(&bout, buf->start, (long)strlen(buf->start));
+	freebuf(buf);
+	if(nflag||tflag){
+		for(n = j->n; n; n = n->next){
+			if(tflag){
+				if(!(n->flags&VIRTUAL))
+					touch(n->name);
+				else if(explain)
+					Bprint(&bout, "no touch of virtual '%s'\n", n->name);
+			}
+			n->time = time((long *)0);
+			MADESET(n, MADE);
+		}
+	} else {
+		if(DEBUG(D_EXEC))
+			fprint(1, "recipe='%s'\n", j->r->recipe);	/**/
+		Bflush(&bout);
+		if(j->r->attr&NOMINUSE)
+			flags = 0;
+		else
+			flags = "-e";
+		events[slot].pid = execsh(flags, j->r->recipe, 0, e);
+		usage();
+		nrunning++;
+		if(DEBUG(D_EXEC))
+			fprint(1, "pid for target %s = %d\n", wtos(j->t, ' '), events[slot].pid);
+	}
+}
+
+int
+waitup(int echildok, int *retstatus)
+{
+	Envy *e;
+	int pid;
+	int slot;
+	Symtab *s;
+	Word *w;
+	Job *j;
+	char buf[ERRMAX];
+	Bufblock *bp;
+	int uarg = 0;
+	int done;
+	Node *n;
+	Process *p;
+	extern int runerrs;
+
+	/* first check against the proces slist */
+	if(retstatus)
+		for(p = phead; p; p = p->f)
+			if(p->pid == *retstatus){
+				*retstatus = p->status;
+				pdelete(p);
+				return(-1);
+			}
+again:		/* rogue processes */
+	pid = waitfor(buf);
+	if(pid == -1){
+		if(echildok > 0)
+			return(1);
+		else {
+			fprint(2, "mk: (waitup %d) ", echildok);
+			perror("mk wait");
+			Exit();
+		}
+	}
+	if(DEBUG(D_EXEC))
+		fprint(1, "waitup got pid=%d, status='%s'\n", pid, buf);
+	if(retstatus && pid == *retstatus){
+		*retstatus = buf[0]? 1:0;
+		return(-1);
+	}
+	slot = pidslot(pid);
+	if(slot < 0){
+		if(DEBUG(D_EXEC))
+			fprint(2, "mk: wait returned unexpected process %d\n", pid);
+		pnew(pid, buf[0]? 1:0);
+		goto again;
+	}
+	j = events[slot].job;
+	usage();
+	nrunning--;
+	events[slot].pid = -1;
+	if(buf[0]){
+		e = buildenv(j, slot);
+		bp = newbuf();
+		shprint(j->r->recipe, e, bp);
+		front(bp->start);
+		fprint(2, "mk: %s: exit status=%s", bp->start, buf);
+		freebuf(bp);
+		for(n = j->n, done = 0; n; n = n->next)
+			if(n->flags&DELETE){
+				if(done++ == 0)
+					fprint(2, ", deleting");
+				fprint(2, " '%s'", n->name);
+				delete(n->name);
+			}
+		fprint(2, "\n");
+		if(kflag){
+			runerrs++;
+			uarg = 1;
+		} else {
+			jobs = 0;
+			Exit();
+		}
+	}
+	for(w = j->t; w; w = w->next){
+		if((s = symlook(w->s, S_NODE, 0)) == 0)
+			continue;	/* not interested in this node */
+		update(uarg, s->u.ptr);
+	}
+	if(nrunning < nproclimit)
+		sched();
+	return(0);
+}
+
+void
+nproc(void)
+{
+	Symtab *sym;
+	Word *w;
+
+	if(sym = symlook("NPROC", S_VAR, 0)) {
+		w = sym->u.ptr;
+		if (w && w->s && w->s[0])
+			nproclimit = atoi(w->s);
+	}
+	if(nproclimit < 1)
+		nproclimit = 1;
+	if(DEBUG(D_EXEC))
+		fprint(1, "nprocs = %d\n", nproclimit);
+	if(nproclimit > nevents){
+		if(nevents)
+			events = (Event *)Realloc((char *)events, nproclimit*sizeof(Event));
+		else
+			events = (Event *)Malloc(nproclimit*sizeof(Event));
+		while(nevents < nproclimit)
+			events[nevents++].pid = 0;
+	}
+}
+
+int
+nextslot(void)
+{
+	int i;
+
+	for(i = 0; i < nproclimit; i++)
+		if(events[i].pid <= 0) return i;
+	assert(/*out of slots!!*/ 0);
+	return 0;	/* cyntax */
+}
+
+int
+pidslot(int pid)
+{
+	int i;
+
+	for(i = 0; i < nevents; i++)
+		if(events[i].pid == pid) return(i);
+	if(DEBUG(D_EXEC))
+		fprint(2, "mk: wait returned unexpected process %d\n", pid);
+	return(-1);
+}
+
+
+static void
+pnew(int pid, int status)
+{
+	Process *p;
+
+	if(pfree){
+		p = pfree;
+		pfree = p->f;
+	} else
+		p = (Process *)Malloc(sizeof(Process));
+	p->pid = pid;
+	p->status = status;
+	p->f = phead;
+	phead = p;
+	if(p->f)
+		p->f->b = p;
+	p->b = 0;
+}
+
+static void
+pdelete(Process *p)
+{
+	if(p->f)
+		p->f->b = p->b;
+	if(p->b)
+		p->b->f = p->f;
+	else
+		phead = p->f;
+	p->f = pfree;
+	pfree = p;
+}
+
+void
+killchildren(char *msg)
+{
+	Process *p;
+
+	kflag = 1;	/* to make sure waitup doesn't exit */
+	jobs = 0;	/* make sure no more get scheduled */
+	for(p = phead; p; p = p->f)
+		expunge(p->pid, msg);
+	while(waitup(1, (int *)0) == 0)
+		;
+	Bprint(&bout, "mk: %s\n", msg);
+	Exit();
+}
+
+static long tslot[1000];
+static long tick;
+
+void
+usage(void)
+{
+	long t;
+
+	time(&t);
+	if(tick)
+		tslot[nrunning] += (t-tick);
+	tick = t;
+}
+
+void
+prusage(void)
+{
+	int i;
+
+	usage();
+	for(i = 0; i <= nevents; i++)
+		fprint(1, "%d: %ld\n", i, tslot[i]);
+}
diff --git a/sys/src/cmd/mk/shprint.c b/sys/src/cmd/mk/shprint.c
new file mode 100755
index 000000000..7f5cf30bf
--- /dev/null
+++ b/sys/src/cmd/mk/shprint.c
@@ -0,0 +1,90 @@
+#include	"mk.h"
+
+static char *vexpand(char*, Envy*, Bufblock*);
+static char *shquote(char*, Rune, Bufblock*);
+static char *shbquote(char*, Bufblock*);
+
+void
+shprint(char *s, Envy *env, Bufblock *buf)
+{
+	int n;
+	Rune r;
+
+	while(*s) {
+		n = chartorune(&r, s);
+		if (r == '$')
+			s = vexpand(s, env, buf);
+		else {
+			rinsert(buf, r);
+			s += n;
+			s = copyq(s, r, buf);	/*handle quoted strings*/
+		}
+	}
+	insert(buf, 0);
+}
+
+static char *
+mygetenv(char *name, Envy *env)
+{
+	if (!env)
+		return 0;
+	if (symlook(name, S_WESET, 0) == 0 && symlook(name, S_INTERNAL, 0) == 0)
+		return 0;
+		/* only resolve internal variables and variables we've set */
+	for(; env->name; env++){
+		if (strcmp(env->name, name) == 0)
+			return wtos(env->values, ' ');
+	}
+	return 0;
+}
+
+static char *
+vexpand(char *w, Envy *env, Bufblock *buf)
+{
+	char *s, carry, *p, *q;
+
+	assert(/*vexpand no $*/ *w == '$');
+	p = w+1;	/* skip dollar sign */
+	if(*p == '{') {
+		p++;
+		q = utfrune(p, '}');
+		if (!q)
+			q = strchr(p, 0);
+	} else
+		q = shname(p);
+	carry = *q;
+	*q = 0;
+	s = mygetenv(p, env);
+	*q = carry;
+	if (carry == '}')
+		q++;
+	if (s) {
+		bufcpy(buf, s, strlen(s));
+		free(s);
+	} else 		/* copy name intact*/
+		bufcpy(buf, w, q-w);
+	return(q);
+}
+
+void
+front(char *s)
+{
+	char *t, *q;
+	int i, j;
+	char *flds[512];
+
+	q = strdup(s);
+	i = getfields(q, flds, nelem(flds), 0, " \t\n");
+	if(i > 5){
+		flds[4] = flds[i-1];
+		flds[3] = "...";
+		i = 5;
+	}
+	t = s;
+	for(j = 0; j < i; j++){
+		for(s = flds[j]; *s; *t++ = *s++);
+		*t++ = ' ';
+	}
+	*t = 0;
+	free(q);
+}
diff --git a/sys/src/cmd/mk/symtab.c b/sys/src/cmd/mk/symtab.c
new file mode 100755
index 000000000..57129ae67
--- /dev/null
+++ b/sys/src/cmd/mk/symtab.c
@@ -0,0 +1,95 @@
+#include	"mk.h"
+
+#define	NHASH	4099
+#define	HASHMUL	79L	/* this is a good value */
+static Symtab *hash[NHASH];
+
+void
+syminit(void)
+{
+	Symtab **s, *ss;
+
+	for(s = hash; s < &hash[NHASH]; s++){
+		for(ss = *s; ss; ss = ss->next)
+			free((char *)ss);
+		*s = 0;
+	}
+}
+
+Symtab *
+symlook(char *sym, int space, void *install)
+{
+	long h;
+	char *p;
+	Symtab *s;
+
+	for(p = sym, h = space; *p; h += *p++)
+		h *= HASHMUL;
+	if(h < 0)
+		h = ~h;
+	h %= NHASH;
+	for(s = hash[h]; s; s = s->next)
+		if((s->space == space) && (strcmp(s->name, sym) == 0))
+			return(s);
+	if(install == 0)
+		return(0);
+	s = (Symtab *)Malloc(sizeof(Symtab));
+	s->space = space;
+	s->name = sym;
+	s->u.ptr = install;
+	s->next = hash[h];
+	hash[h] = s;
+	return(s);
+}
+
+void
+symdel(char *sym, int space)
+{
+	long h;
+	char *p;
+	Symtab *s, *ls;
+
+	/* multiple memory leaks */
+
+	for(p = sym, h = space; *p; h += *p++)
+		h *= HASHMUL;
+	if(h < 0)
+		h = ~h;
+	h %= NHASH;
+	for(s = hash[h], ls = 0; s; ls = s, s = s->next)
+		if((s->space == space) && (strcmp(s->name, sym) == 0)){
+			if(ls)
+				ls->next = s->next;
+			else
+				hash[h] = s->next;
+			free((char *)s);
+		}
+}
+
+void
+symtraverse(int space, void (*fn)(Symtab*))
+{
+	Symtab **s, *ss;
+
+	for(s = hash; s < &hash[NHASH]; s++)
+		for(ss = *s; ss; ss = ss->next)
+			if(ss->space == space)
+				(*fn)(ss);
+}
+
+void
+symstat(void)
+{
+	Symtab **s, *ss;
+	int n;
+	int l[1000];
+
+	memset((char *)l, 0, sizeof(l));
+	for(s = hash; s < &hash[NHASH]; s++){
+		for(ss = *s, n = 0; ss; ss = ss->next)
+			n++;
+		l[n]++;
+	}
+	for(n = 0; n < 1000; n++)
+		if(l[n]) Bprint(&bout, "%d of length %d\n", l[n], n);
+}
diff --git a/sys/src/cmd/mk/var.c b/sys/src/cmd/mk/var.c
new file mode 100755
index 000000000..94e813f5f
--- /dev/null
+++ b/sys/src/cmd/mk/var.c
@@ -0,0 +1,41 @@
+#include	"mk.h"
+
+void
+setvar(char *name, void *value)
+{
+	symlook(name, S_VAR, value)->u.ptr = value;
+	symlook(name, S_MAKEVAR, (void*)"");
+}
+
+static void
+print1(Symtab *s)
+{
+	Word *w;
+
+	Bprint(&bout, "\t%s=", s->name);
+	for (w = s->u.ptr; w; w = w->next)
+		Bprint(&bout, "'%s'", w->s);
+	Bprint(&bout, "\n");
+}
+
+void
+dumpv(char *s)
+{
+	Bprint(&bout, "%s:\n", s);
+	symtraverse(S_VAR, print1);
+}
+
+char *
+shname(char *a)
+{
+	Rune r;
+	int n;
+
+	while (*a) {
+		n = chartorune(&r, a);
+		if (!WORDCHR(r))
+			break;
+		a += n;
+	}
+	return a;
+}
diff --git a/sys/src/cmd/mk/varsub.c b/sys/src/cmd/mk/varsub.c
new file mode 100755
index 000000000..aaf9c512b
--- /dev/null
+++ b/sys/src/cmd/mk/varsub.c
@@ -0,0 +1,252 @@
+#include	"mk.h"
+
+static	Word		*subsub(Word*, char*, char*);
+static	Word		*expandvar(char**);
+static	Bufblock	*varname(char**);
+static	Word		*extractpat(char*, char**, char*, char*);
+static	int		submatch(char*, Word*, Word*, int*, char**);
+static	Word		*varmatch(char *);
+
+Word *
+varsub(char **s)
+{
+	Bufblock *b;
+	Word *w;
+
+	if(**s == '{')		/* either ${name} or ${name: A%B==C%D}*/
+		return expandvar(s);
+
+	b = varname(s);
+	if(b == 0)
+		return 0;
+
+	w = varmatch(b->start);
+	freebuf(b);
+	return w;
+}
+
+/*
+ *	extract a variable name
+ */
+static Bufblock*
+varname(char **s)
+{
+	Bufblock *b;
+	char *cp;
+	Rune r;
+	int n;
+
+	b = newbuf();
+	cp = *s;
+	for(;;){
+		n = chartorune(&r, cp);
+		if (!WORDCHR(r))
+			break;
+		rinsert(b, r);
+		cp += n;
+	}
+	if (b->current == b->start){
+		SYNERR(-1);
+		fprint(2, "missing variable name <%s>\n", *s);
+		freebuf(b);
+		return 0;
+	}
+	*s = cp;
+	insert(b, 0);
+	return b;
+}
+
+static Word*
+varmatch(char *name)
+{
+	Word *w;
+	Symtab *sym;
+	
+	sym = symlook(name, S_VAR, 0);
+	if(sym){
+			/* check for at least one non-NULL value */
+		for (w = sym->u.ptr; w; w = w->next)
+			if(w->s && *w->s)
+				return wdup(w);
+	}
+	return 0;
+}
+
+static Word*
+expandvar(char **s)
+{
+	Word *w;
+	Bufblock *buf;
+	Symtab *sym;
+	char *cp, *begin, *end;
+
+	begin = *s;
+	(*s)++;						/* skip the '{' */
+	buf = varname(s);
+	if (buf == 0)
+		return 0;
+	cp = *s;
+	if (*cp == '}') {				/* ${name} variant*/
+		(*s)++;					/* skip the '}' */
+		w = varmatch(buf->start);
+		freebuf(buf);
+		return w;
+	}
+	if (*cp != ':') {
+		SYNERR(-1);
+		fprint(2, "bad variable name <%s>\n", buf->start);
+		freebuf(buf);
+		return 0;
+	}
+	cp++;
+	end = charin(cp , "}");
+	if(end == 0){
+		SYNERR(-1);
+		fprint(2, "missing '}': %s\n", begin);
+		Exit();
+	}
+	*end = 0;
+	*s = end+1;
+	
+	sym = symlook(buf->start, S_VAR, 0);
+	if(sym == 0 || sym->u.value == 0)
+		w = newword(buf->start);
+	else
+		w = subsub(sym->u.ptr, cp, end);
+	freebuf(buf);
+	return w;
+}
+
+static Word*
+extractpat(char *s, char **r, char *term, char *end)
+{
+	int save;
+	char *cp;
+	Word *w;
+
+	cp = charin(s, term);
+	if(cp){
+		*r = cp;
+		if(cp == s)
+			return 0;
+		save = *cp;
+		*cp = 0;
+		w = stow(s);
+		*cp = save;
+	} else {
+		*r = end;
+		w = stow(s);
+	}
+	return w;
+}
+
+static Word*
+subsub(Word *v, char *s, char *end)
+{
+	int nmid;
+	Word *head, *tail, *w, *h;
+	Word *a, *b, *c, *d;
+	Bufblock *buf;
+	char *cp, *enda;
+
+	a = extractpat(s, &cp, "=%&", end);
+	b = c = d = 0;
+	if(PERCENT(*cp))
+		b = extractpat(cp+1, &cp, "=", end);
+	if(*cp == '=')
+		c = extractpat(cp+1, &cp, "&%", end);
+	if(PERCENT(*cp))
+		d = stow(cp+1);
+	else if(*cp)
+		d = stow(cp);
+
+	head = tail = 0;
+	buf = newbuf();
+	for(; v; v = v->next){
+		h = w = 0;
+		if(submatch(v->s, a, b, &nmid, &enda)){
+			/* enda points to end of A match in source;
+			 * nmid = number of chars between end of A and start of B
+			 */
+			if(c){
+				h = w = wdup(c);
+				while(w->next)
+					w = w->next;
+			}
+			if(PERCENT(*cp) && nmid > 0){	
+				if(w){
+					bufcpy(buf, w->s, strlen(w->s));
+					bufcpy(buf, enda, nmid);
+					insert(buf, 0);
+					free(w->s);
+					w->s = strdup(buf->start);
+				} else {
+					bufcpy(buf, enda, nmid);
+					insert(buf, 0);
+					h = w = newword(buf->start);
+				}
+				buf->current = buf->start;
+			}
+			if(d && *d->s){
+				if(w){
+
+					bufcpy(buf, w->s, strlen(w->s));
+					bufcpy(buf, d->s, strlen(d->s));
+					insert(buf, 0);
+					free(w->s);
+					w->s = strdup(buf->start);
+					w->next = wdup(d->next);
+					while(w->next)
+						w = w->next;
+					buf->current = buf->start;
+				} else
+					h = w = wdup(d);
+			}
+		}
+		if(w == 0)
+			h = w = newword(v->s);
+	
+		if(head == 0)
+			head = h;
+		else
+			tail->next = h;
+		tail = w;
+	}
+	freebuf(buf);
+	delword(a);
+	delword(b);
+	delword(c);
+	delword(d);
+	return head;
+}
+
+static int
+submatch(char *s, Word *a, Word *b, int *nmid, char **enda)
+{
+	Word *w;
+	int n;
+	char *end;
+
+	n = 0;
+	for(w = a; w; w = w->next){
+		n = strlen(w->s);
+		if(strncmp(s, w->s, n) == 0)
+			break;
+	}
+	if(a && w == 0)		/*  a == NULL matches everything*/
+		return 0;
+
+	*enda = s+n;		/* pointer to end a A part match */
+	*nmid = strlen(s)-n;	/* size of remainder of source */
+	end = *enda+*nmid;
+	for(w = b; w; w = w->next){
+		n = strlen(w->s);
+		if(strcmp(w->s, end-n) == 0){
+			*nmid -= n;
+			break;
+		}
+	}
+	if(b && w == 0)		/* b == NULL matches everything */
+		return 0;
+	return 1;
+}
diff --git a/sys/src/cmd/mk/word.c b/sys/src/cmd/mk/word.c
new file mode 100755
index 000000000..ac92cacaf
--- /dev/null
+++ b/sys/src/cmd/mk/word.c
@@ -0,0 +1,189 @@
+#include	"mk.h"
+
+static	Word	*nextword(char**);
+
+Word*
+newword(char *s)
+{
+	Word *w;
+
+	w = (Word *)Malloc(sizeof(Word));
+	w->s = strdup(s);
+	w->next = 0;
+	return(w);
+}
+
+Word *
+stow(char *s)
+{
+	Word *head, *w, *new;
+
+	w = head = 0;
+	while(*s){
+		new = nextword(&s);
+		if(new == 0)
+			break;
+		if (w)
+			w->next = new;
+		else
+			head = w = new;
+		while(w->next)
+			w = w->next;
+		
+	}
+	if (!head)
+		head = newword("");
+	return(head);
+}
+
+char *
+wtos(Word *w, int sep)
+{
+	Bufblock *buf;
+	char *cp;
+
+	buf = newbuf();
+	for(; w; w = w->next){
+		for(cp = w->s; *cp; cp++)
+			insert(buf, *cp);
+		if(w->next)
+			insert(buf, sep);
+	}
+	insert(buf, 0);
+	cp = strdup(buf->start);
+	freebuf(buf);
+	return(cp);
+}
+
+Word*
+wdup(Word *w)
+{
+	Word *v, *new, *base;
+
+	v = base = 0;
+	while(w){
+		new = newword(w->s);
+		if(v)
+			v->next = new;
+		else
+			base = new;
+		v = new;
+		w = w->next;
+	}
+	return base;
+}
+
+void
+delword(Word *w)
+{
+	Word *v;
+
+	while(v = w){
+		w = w->next;
+		if(v->s)
+			free(v->s);
+		free(v);
+	}
+}
+
+/*
+ *	break out a word from a string handling quotes, executions,
+ *	and variable expansions.
+ */
+static Word*
+nextword(char **s)
+{
+	Bufblock *b;
+	Word *head, *tail, *w;
+	Rune r;
+	char *cp;
+	int empty;
+
+	cp = *s;
+	b = newbuf();
+restart:
+	head = tail = 0;
+	while(*cp == ' ' || *cp == '\t')		/* leading white space */
+		cp++;
+	empty = 1;
+	while(*cp){
+		cp += chartorune(&r, cp);
+		switch(r)
+		{
+		case ' ':
+		case '\t':
+		case '\n':
+			goto out;
+		case '\\':
+		case '\'':
+		case '"':
+			empty = 0;
+			cp = expandquote(cp, r, b);
+			if(cp == 0){
+				fprint(2, "missing closing quote: %s\n", *s);
+				Exit();
+			}
+			break;
+		case '$':
+			w = varsub(&cp);
+			if(w == 0){
+				if(empty)
+					goto restart;
+				break;
+			}
+			empty = 0;
+			if(b->current != b->start){
+				bufcpy(b, w->s, strlen(w->s));
+				insert(b, 0);
+				free(w->s);
+				w->s = strdup(b->start);
+				b->current = b->start;
+			}
+			if(head){
+				bufcpy(b, tail->s, strlen(tail->s));
+				bufcpy(b, w->s, strlen(w->s));
+				insert(b, 0);
+				free(tail->s);
+				tail->s = strdup(b->start);
+				tail->next = w->next;
+				free(w->s);
+				free(w);
+				b->current = b->start;
+			} else
+				tail = head = w;
+			while(tail->next)
+				tail = tail->next;
+			break;
+		default:
+			empty = 0;
+			rinsert(b, r);
+			break;
+		}
+	}
+out:
+	*s = cp;
+	if(b->current != b->start){
+		if(head){
+			cp = b->current;
+			bufcpy(b, tail->s, strlen(tail->s));
+			bufcpy(b, b->start, cp-b->start);
+			insert(b, 0);
+			free(tail->s);
+			tail->s = strdup(cp);
+		} else {
+			insert(b, 0);
+			head = newword(b->start);
+		}
+	}
+	freebuf(b);
+	return head;
+}
+
+void
+dumpw(char *s, Word *w)
+{
+	Bprint(&bout, "%s", s);
+	for(; w; w = w->next)
+		Bprint(&bout, " '%s'", w->s);
+	Bputc(&bout, '\n');
+}