interp: support "cd -" as "cd $OLDPWD"

As per https://www.man7.org/linux/man-pages/man1/cd.1p.html#OPERANDS. Signed-off-by: donorp <[email protected]>
riacataquian · Dec 2, 2021 · 1963ae1 · 1963ae1
1 parent e482fb8
commit 1963ae1
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diff --git a/interp/builtin.go b/interp/builtin.go
@@ -214,6 +214,12 @@ func (r *Runner) builtinCode(ctx context.Context, pos syntax.Pos, name string, a
 			path = r.envGet("HOME")
 		case 1:
 			path = args[0]
+
+			// replicate the commonly implemented behavior of `cd -`
+			// ref: https://www.man7.org/linux/man-pages/man1/cd.1p.html#OPERANDS
+			if path == "-" {
+				path = r.envGet("OLDPWD")
+			}
 		default:
 			r.errf("usage: cd [dir]\n")
 			return 2

diff --git a/interp/interp_test.go b/interp/interp_test.go
@@ -936,6 +936,10 @@ var runTests = []runTest{
 		`mkdir a; ln -s a b; [[ "$(cd a && pwd -P)" == "$(cd b && pwd -L)" ]]; echo $?`,
 		"1\n",
 	},
+	{
+		`orig="$PWD"; mkdir a; cd a; cd -; [[ "$PWD" == "$orig" ]]`,
+		"",
+	},
 
 	// dirs/pushd/popd
 	{"set -- $(dirs); echo $# ${#DIRSTACK[@]}", "1 1\n"},