Return an exit code without closing shell

Question

I'd like to return an exit code from a BASH script that is called within another script, but could also be called directly. It roughly looks like this:

#!/bin/bash
dq2-get $1
if [ $? -ne 0 ]; then
  echo "ERROR: ..."
  # EXIT HERE
fi
# extract, do some stuff
# ...

Now in the line EXIT HERE the script should exit and return exit code 1. The problem is that

• I cannot use return, because when I forget to source the script instead of calling it, return will not exit, and the rest of the script will be executed and mess things up.
• I cannot use exit, because this closes the shell.
• I cannot use the nice trick kill -SIGINT $$, because this doesn't allow to return an exit code.

Is there any viable alternative that I have overlooked?

Answer 1

The answer to the question title (not in the body as other answers have addressed) is:

Return an exit code without closing shell

(exit 33)

If you need to have -e active and still avoid exiting the shell with a non-zero exit code, then do:

(exit 33) && true

The true command is never executed but is used to build a compound command that is not exited by the -e shell flag.

That sets the exit code without exiting the shell (nor a sourced script).

For the more complex question of exiting (with an specific exit code) either if executed or sourced:

#!/bin/bash
[ "$BASH_SOURCE" == "$0" ] &&
    echo "This file is meant to be sourced, not executed" && 
        exit 30

return 88

Will set an exit code of 30 (with an error message) if executed.
And an exit code of 88 if sourced. Will exit both the execution or the sourcing without affecting the calling shell.

Answer 2

Use this instead of exit or return:

[ $PS1 ] && return || exit;

Works whether sourced or not.

Answer 3

You can use x"${BASH_SOURCE[0]}" == x"$0" to test if the script was sourced or called (false if sourced, true if called) and return or exit accordingly.

Answer 4

Another option is to use a function and put the return values in that and then simply either source the script (source processStatus.sh) or call the script (./processStatus.sh) . For example consider the processStatus.sh script that needs to return a value to the stopProcess.sh script but also needs to be called separately from say the command line without using source (only relevant parts included) Eg:

check_process ()
{
  if [ "$1" -eq "50" ]
  then
    return 1       
  else
    return 0
  fi       
}

and

source processStatus.sh $1
RET_VALUE=$?
if [ "$RET_VALUE" -ne "0" ]
then
  exit 0
fi

Answer 5

You can use return if you use set -e in the beginning of the script.

If you just want to check if the function returned no errors, I'd rather suggest rewriting your code like this:

#!/bin/bash

set -e # exit program if encountered errors

dq2-get ()
{
  # define the function here
  # ...
  if [ $1 -eq 0 ]
  then
    return 0
  else
    return 255
  # Note that nothing will execute from this point on,
  # because `return` terminates the function.
}

# ...
# lots of code ...
# ...

# Now, the test:
# This won't exit the program.
if $(dq2-get $1); then
  echo "No errors, everything's fine"
else
  echo "ERROR: ..."
fi
# These commands execute anyway, no matter what
# `dq2-get $1` returns (i.e. {0..255}).
# extract, do some stuff
# ...

Now, the code above won't leave the program if the function dq2-get $1 returns errors. But, implementing the function all by itself will exit the program because of the set -e. The code below describes this situation:

# The function below will stop the program and exit
# if it returns anything other than `0`
# since `set -e` means stop if encountered any errors.
$(dq2-get $1)
# These commands execute ONLY if `dq2-get $1` returns `0`
# extract, do some stuff
# ...

Answer 6

Thanks for the question, my case was to source a file for some setup, but end the script and skip the setup actions if certain conditions were not met.

I had hit the issue of an attempt to use exit() actually causing the closing of my terminal, and found myself here :D

After reviewing the options for the specific solution i just went with something like the below, I also think Deepaks answer is worth reviewing if this approach works in your case.

if [ -z "$REQUIRED_VAR" ]; then
  echo "please check/set \$REQUIRED_VAR ..."
  echo "skipping logic"
else
  echo "starting logic"
  doStuff()
  echo "completed logic"
fi