From a948b7f5466e79b0d4f22cf36a6f5fa764029eab Mon Sep 17 00:00:00 2001
From: Timo Hirvonen <tihirvon@gmail.com>
Date: Sat, 26 Apr 2014 20:12:09 +0300
Subject: [PATCH] Bash-like "cd -"

---
 Documentation/dex.txt |  3 ++-
 commands.c            | 10 +++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/dex.txt b/Documentation/dex.txt
index 320328e..e173c47 100644
--- a/Documentation/dex.txt
+++ b/Documentation/dex.txt
@@ -112,7 +112,8 @@ case [-lu]
 	-u upper case
 
 cd <directory>
-	Change directory. Updates $PWD and $OLDPWD.
+	Change directory. Updates $PWD and $OLDPWD. "cd -" changes to
+	previous directory ($OLDPWD).
 
 center-view
 	Center view to cursor.
diff --git a/commands.c b/commands.c
index 011f765..e0d9480 100644
--- a/commands.c
+++ b/commands.c
@@ -87,12 +87,20 @@ static void cmd_case(const char *pf, char **args)
 
 static void cmd_cd(const char *pf, char **args)
 {
+	char *dir = args[0];
 	char cwd[8192];
 	char *cwdp = NULL;
 	bool got_cwd = !!getcwd(cwd, sizeof(cwd));
 	int i;
 
-	if (chdir(args[0])) {
+	if (streq(dir, "-")) {
+		dir = getenv("OLDPWD");
+		if (dir == NULL || dir[0] == 0) {
+			error_msg("cd: OLDPWD not set");
+			return;
+		}
+	}
+	if (chdir(dir)) {
 		error_msg("cd: %s", strerror(errno));
 		return;
 	}