Is there anyway to know when the entry generating command has exited non-zero?

[dkuettel]

Hi,

I'm using fzf with --bind 'start:reload:some command' and I don't know if there is a way to detect that this command, even though it generated some entries, failed and exited with a non-zero exit code. It's impossible to tell as a user, since you do get many entries.

Cheers, Daniel.

[fsc0]

How about this approach.

#!/usr/bin/env bash
_some_command()
{
	# when $PWD is empty
	if [[ -z "$(ls -A)" ]]; then
		return 100
	fi
}
export -f _some_command

fzf \
	--bind 'start:transform:
		_some_command
		_exit_status="$?"
		if (( _exit_status > 0 )); then
			echo "change-prompt($_exit_status )"
		fi'

[LangLangBart]

Note

fzf runs the command with $SHELL -c if SHELL is set, otherwise with sh -c

You could try redirecting stderr to a file and deducing the issue from there. The --with-shell¹ flag allows you to specify the executable (e.g., zsh) and optional pass additional options (e.g., -x). Here are some examples:

fzf \
  --bind 'start:reload:exec 2>/tmp/debug.log; echo HI; foobar; echo "exit status $?" >&2' \
  --with-shell 'zsh -fvxc'

cat /tmp/debug.log
+zsh:1> echo HI
+zsh:1> foobar
zsh:1: command not found: foobar
+zsh:1> echo 'exit status 127'
exit status 127

fzf \
  --bind 'start:reload:exec 2>/tmp/debug.log; echo HI; grep foobar /non/existing/directory; echo "exit status $?" >&2' \
  --with-shell 'zsh -fvxc'

cat /tmp/debug.log
+zsh:1> echo HI
+zsh:1> grep foobar /non/existing/directory
grep: /non/existing/directory: No such file or directory
+zsh:1> echo 'exit status 2'
exit status 2

Footnotes

1. fzf/CHANGELOG.md 0.51.0 ↩

[junegunn]

Another way is to use the --listen option:

fzf --listen --header-border --bind 'start:reload:
  echo foo
  sleep 1
  invalid-command || curl localhost:$FZF_PORT -d "change-header:Command failed"
'

[dkuettel]

Those are very interesting approaches, I will play around with them. Thanks for that. I actually wasnt aware of the whole transform family of operations.

A kinda nuclear solution that I found is like this: --bind 'start:reload:command arg1 arg2 || pkill --session 0 fzf'