diff --git a/environ.c b/environ.c
index 353b84fa..4c4af98f 100644
--- a/environ.c
+++ b/environ.c
@@ -35,12 +35,14 @@ environ_cmp(struct environ_entry *envent1, struct environ_entry *envent2)
 	return (strcmp(envent1->name, envent2->name));
 }
 
+/* Initialise the environment. */
 void
 environ_init(struct environ *env)
 {
 	RB_INIT(env);
 }
 
+/* Free an environment. */
 void
 environ_free(struct environ *env)
 {
@@ -56,6 +58,7 @@ environ_free(struct environ *env)
 	}
 }
 
+/* Copy one environment into another. */
 void
 environ_copy(struct environ *srcenv, struct environ *dstenv)
 {
@@ -65,6 +68,7 @@ environ_copy(struct environ *srcenv, struct environ *dstenv)
 		environ_set(dstenv, envent->name, envent->value);
 }
 
+/* Find an environment variable. */
 struct environ_entry *
 environ_find(struct environ *env, const char *name)
 {
@@ -74,6 +78,7 @@ environ_find(struct environ *env, const char *name)
 	return (RB_FIND(environ, env, &envent));
 }
 
+/* Set an environment variable. */
 void
 environ_set(struct environ *env, const char *name, const char *value)
 {
@@ -97,10 +102,11 @@ environ_set(struct environ *env, const char *name, const char *value)
 	}
 }
 
+/* Set an environment variable from a NAME=VALUE string. */
 void
 environ_put(struct environ *env, const char *var)
 {
-	char		*name, *value;
+	char	*name, *value;
 
 	value = strchr(var, '=');
 	if (value == NULL)
@@ -114,6 +120,7 @@ environ_put(struct environ *env, const char *var)
 	xfree(name);
 }
 
+/* Unset an environment variable. */
 void
 environ_unset(struct environ *env, const char *name)
 {
@@ -128,6 +135,10 @@ environ_unset(struct environ *env, const char *name)
 	xfree(envent);
 }
 
+/*
+ * Copy a space-separated list of variables from a destination into a source
+ * environment.
+ */
 void
 environ_update(const char *vars, struct environ *srcenv, struct environ *dstenv)
 {
@@ -143,3 +154,28 @@ environ_update(const char *vars, struct environ *srcenv, struct environ *dstenv)
 	}
 	xfree(copyvars);
 }
+
+/* Push environment into the real environment - use after fork(). */
+void
+environ_push(struct environ *env)
+{
+	ARRAY_DECL(, char *)	varlist;
+	struct environ_entry   *envent;
+	char		      **varp, *var;
+	u_int			i;
+
+	ARRAY_INIT(&varlist);
+	for (varp = environ; *varp != NULL; varp++) {
+		var = xstrdup(*varp);
+		var[strcspn(var, "=")] = '\0';
+		ARRAY_ADD(&varlist, var);
+	}
+	for (i = 0; i < ARRAY_LENGTH(&varlist); i++)
+		unsetenv(ARRAY_ITEM(&varlist, i));
+	ARRAY_FREE(&varlist);
+
+	RB_FOREACH(envent, environ, env) {
+		if (envent->value != NULL)
+			setenv(envent->name, envent->value, 1);
+	}
+}
diff --git a/job.c b/job.c
index 36ea2f4e..ddeae13f 100644
--- a/job.c
+++ b/job.c
@@ -150,7 +150,8 @@ job_run(struct job *job)
 		return (-1);
 	case 0:		/* child */
 		server_signal_clear();
-		/* XXX environ? */
+
+		environ_push(&global_environ);
 
 		if (dup2(out[1], STDOUT_FILENO) == -1)
 			fatal("dup2 failed");
diff --git a/tmux.1 b/tmux.1
index 351aec44..dc590c7e 100644
--- a/tmux.1
+++ b/tmux.1
@@ -1745,6 +1745,10 @@ the
 .Ic status-interval
 option: if the status line is redrawn in the meantime, the previous result is
 used.
+Shell commands are executed with the
+.Nm
+global environment set (see the
+.Sx ENVIRONMENT section).
 .Pp
 #[attributes] allows a comma-separated list of attributes to be specified,
 these may be
diff --git a/tmux.h b/tmux.h
index 576c4977..642d5530 100644
--- a/tmux.h
+++ b/tmux.h
@@ -1330,6 +1330,7 @@ void	environ_set(struct environ *, const char *, const char *);
 void	environ_put(struct environ *, const char *);
 void	environ_unset(struct environ *, const char *);
 void	environ_update(const char *, struct environ *, struct environ *);
+void	environ_push(struct environ *);
 
 /* tty.c */
 void	tty_raw(struct tty *, const char *);
diff --git a/window.c b/window.c
index 4a801a76..00c03f6e 100644
--- a/window.c
+++ b/window.c
@@ -480,14 +480,11 @@ int
 window_pane_spawn(struct window_pane *wp, const char *cmd, const char *shell,
     const char *cwd, struct environ *env, struct termios *tio, char **cause)
 {
-	struct winsize	 	 ws;
-	int		 	 mode;
-	char			*argv0, **varp, *var;
-	ARRAY_DECL(, char *)	 varlist;
-	struct environ_entry	*envent;
-	const char		*ptr;
-	struct termios		 tio2;
-	u_int		 	 i;
+	struct winsize	 ws;
+	int		 mode;
+	char		*argv0;
+	const char	*ptr;
+	struct termios	 tio2;
 
 	if (wp->fd != -1) {
 		close(wp->fd);
@@ -530,20 +527,7 @@ window_pane_spawn(struct window_pane *wp, const char *cmd, const char *shell,
 		if (tcsetattr(STDIN_FILENO, TCSANOW, &tio2) != 0)
 			fatal("tcgetattr failed");
 
-		ARRAY_INIT(&varlist);
-		for (varp = environ; *varp != NULL; varp++) {
-			var = xstrdup(*varp);
-			var[strcspn(var, "=")] = '\0';
-			ARRAY_ADD(&varlist, var);
-		}
-		for (i = 0; i < ARRAY_LENGTH(&varlist); i++) {
-			var = ARRAY_ITEM(&varlist, i);
-			unsetenv(var);
-		}
-		RB_FOREACH(envent, environ, env) {
-			if (envent->value != NULL)
-				setenv(envent->name, envent->value, 1);
-		}
+		environ_push(env);
 
 		server_signal_clear();
 		log_close();