Exit code from child script to parent script

Question

I have the below parent script which calls a child script.

parent.sh

#!/bin/bash
export home=`pwd`
echo "calling child"
. ${home}/bin/child.sh
retn_code=$?
if (retn_code -ne 0)
then
    exit $retn_code
else
    echo "successful"
fi
exit 0

child.sh:

#!/bin/bash
exit 1

When I execute the parent script, the exit status of 1 is not getting captured in parent script. The last line of the log printed is "calling child" and there are no lines printed after that in log.

Is there something I am missing while getting the exit status from child to parent?

Ok.. apologies.i am new to scripting. In this case, how to pass the exit status from the subscript to main script? — Padfoot123, Mar 11 '21 at 15:09
If the script is meant to be sourced - `return`. If the script is meant to be run as separate child, then don't source it. — KamilCuk, Mar 11 '21 at 15:10
`if ./bin/child.sh; then echo "successful"; else exit; fi` -- and notice it's not using the `.` command anymore. — Charles Duffy, Mar 11 '21 at 15:10
The marked duplicate is not really a duplicate. The issue here is not numerical comparison but an incorrect use of `.` — William Pursell, Mar 11 '21 at 15:11
@WilliamPursell, granted, but I'm calling that a typo. Can add an additional duplicate for it if you feel strongly, though. — Charles Duffy, Mar 11 '21 at 15:11
BTW, consider `home=$PWD` instead of `home=$(pwd)`; the former is considerably faster to run. — Charles Duffy, Mar 11 '21 at 15:17
`rc=$?; [[ $rc = 0 ]] || exit $rc` This answered my own question, may answer this Q: https://stackoverflow.com/questions/90418/exit-shell-script-based-on-process-exit-code — Jesse, Aug 27 '22 at 06:15

William Pursell · Accepted Answer · 2021-03-11T15:20:06.593

2

. does not call the child, it runs its code. So if the child script calls exit, the parent exits. You want to do:

#!/bin/bash
home=$(pwd)
echo "calling child"
if "${home}"/bin/child.sh; then
    echo success
else
    exit   # status returned by child will propagate
fi
exit 0

Note that it's very odd to use the variable home here. If you want it defined in child.sh, IMO it would be clearer to write if home=$(pwd) ./bin/child.sh; then .... Your usage of export implies that you want it defined in child.sh, but I suspect you don't actually want that. It's not pertinent to the question, so I've just removed what I believe is an unnecessary export.

edited Mar 11 '21 at 15:20

answered Mar 11 '21 at 15:11

William Pursell

204,365
48
270
300

This could/should have been marked duplicate of https://stackoverflow.com/questions/922651/unix-command-line-execute-with-dot-vs-without -- I was about to edit the duplicate list to add that when you reopened. – Charles Duffy Mar 11 '21 at 15:12
2

BTW, your `if` is backwards; it's currently `exit`ing in the success case, and echoing `successful` in the failure case. – Charles Duffy Mar 11 '21 at 15:13
...whereas in the new version because the `!` is inverting `$?`, the `exit` no longer propagates the intended value. – Charles Duffy Mar 11 '21 at 15:13
@Biffen, `exit` uses `$?` by default, really. The trick (which early versions of this answer haven't gotten right) is to write the code so the child's exit status is still _in_ `$?` when the `exit` is reached. – Charles Duffy Mar 11 '21 at 15:13
@CharlesDuffy Reversed the logic to match the OP. Agree that this should be marked duplicate, but not sure of what. – William Pursell Mar 11 '21 at 15:14

Exit code from child script to parent script

1 Answers1