How can I ignore an error in a command?

[mortoray]

There are some commands for which I want to ignore error returns and continue processing. Is there a way to mark a line as ignoring the return value?

This came up with killall which I used to end a process that may or may not be there. The current alternative I have is killall some_proce || true, though that seems like a bash thing, not a justfile thing.

[casey]

I think that currently, foo || true is the best way to do this. If you have a lot of commands you'd like to ignore errors for, you can switch to using a shebang recipe, which behaves like a normal shell script with respect to error codes, i.e. ignores them:

foo:
  #!/usr/bin/env sh
  cat bar

Make actually has a feature for this. If you put - in front of a command, it will ignore errors:

$ cat Makefile
foo:
  exit 1
$ make
exit 1
make: *** [foo] Error 1

$ cat Makefile
foo:
  -exit 1
$ make
exit 1
make: [foo] Error 1 (ignored)

It's a bit magical, but I wouldn't be opposed to adding this feature to Just. It would also make a great first issue for anyone interested.

[iwillspeak]

I've taken a stab at implemnting this feature in #687 .

[casey]

This has been done! Thank you very much, @iwillspeak. I added some documentation in the readme, and cut v0.8.0 that includes the feature. Technically, this is a breaking change, which is why the minor version was bumped to 8, but I don't think it will be a problem in practice, since someone would have to have a recipe line starting with -.