diff --git a/src/cmd/mk/env.c b/src/cmd/mk/env.c
new file mode 100644
index 0000000..c040db5
--- /dev/null
+++ b/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, (Word *) s->value);
+}
+
+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));
+	sprint(buf, "%d", getpid());
+	envupd("pid", newword(buf));
+	sprint(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;
+}