best way to fetch the exit code from the redirection document script

Question

if [ ! -z "admin_us" ]
then
newgrp admin_us<< END
 command=` abc.sh `
END
fi
echo $?

What we have seen here is, the exit code is always 0, even if the abc.sh fails, what is a better way to fetch the exit code? The last option for me is to save it in a temporary file and read it outside.

I would say that the exit status is from the `newgrp` command, not `abc.sh`. The question is, when is your code supposed to fail? When `newgrp` fails, or `abc.sh`, or both? It's not clear to me, by the way, why you provide input to `newgrp`. When you run `newgrp admin_us`, it simply ignores any input. — berndbausch, Jul 29 '21 at 07:02
@berndbausch - I need it from the abc.sh , if newgrp fail , then I will anyways get the exit code — Stay Curious, Jul 29 '21 at 07:05
Run `abc.sh`, assign its exit code to a variable e.g. `abc` and its output to another variable e.g. `output`. Use `$output` to perform whatever you want with `newgrp`, then exit with `exit $abc`. — berndbausch, Jul 29 '21 at 07:10

cas · Accepted Answer · 2021-07-29T07:22:50.443

Your heredoc script needs to exit with $? as the exit code.

e.g. minimum-working example (that assumes my UID is a member of users and doesn't require your abc.sh script (uses false instead)

#!/bin/bash
if [ 1 == 1 ]; then
newgrp users << END
 command=$(false)
 exit $?
END
fi
echo $?

NOTE: newgrp forks a new shell, and can't change the value of $command in its parent. You probably want something more like:

if [ ! -z "admin_us" ]; then
  command=$(newgrp admin_us <<<'abc.sh')
fi
echo "$?"
echo "$command"

BTW, don't use backticks. Use $(...) instead. backticks are deprecated, only retained for backwards-compatibility with older shells/scripts. See Have backticks (i.e. cmd) in *sh shells been deprecated?

best way to fetch the exit code from the redirection document script

1 Answers1