[cd-on-quit] How about skip redundant cd commands?

[rennsax]

When NNN_TMPFILE is set, nnn will write the cd command into the tmp file:

nnn/src/nnn.c

Lines 2843 to 2846 in f71b130

	if (fd != -1 && shell_escape(g_buf, sizeof(g_buf), curpath)) {
	dprintf(fd, "cd %s", g_buf);
	close(fd);
	}

But even if the current directory doesn't change, the cd command will still be executed, which make duplicated entries in the directory stack of some shells (like zsh).

How about skip this kind of cd by conditionally writing the command?

I realized it in my personal fork:

dprintf(fd, "[ \"$PWD\" = %s ] || cd %s", g_buf, g_buf);

But I know it's not portable among prevalent shells like fish.

[N-R-K]

You should do this in your quit-cd script instead of in nnn.c.

In fact, nnn shouldn't even write the cd command to begin with and it would've been ideal if we simply wrote the path as is into the file and nothing else. But the cd command was kept to keep existing scripts working.

[N-R-K]

You should do this in your quit-cd script instead of in nnn.c.

To elaborate, I have the following in my own quit-cd script:

# vim: filetype=bash
n3() {
	[ "${NNNLVL:-0}" -ge 1 ] && exit # block nesting

	LESS="${LESS/F/}" nnn "$@"; local ec=$?

	if [ "$ec" -eq 0 ] && [ -f "$NNN_TMPFILE" ]; then
		local to=$(sed "s|^cd '||;s|'$||;s|'\\\''|'|g;" "$NNN_TMPFILE")
		[ "$to" != "$PWD" ] && cd "$to"
	fi
	rm -f "$NNN_TMPFILE" >/dev/null
}

This avoids cd-ing when directory hasn't changed. Additionally, the $ec check makes it avoid changing dir when I quit with Q (non-zero exit code).

I use zsh but I think this should work on bash too.