CODEWITHSUNDEEP
linuxbashexitstatus
Serhii Didanov
Serhii Didanov

Reputation: 2338

Incorrect exit code inside child script

I have a parent script, that execute a child script in background:

#!/bin/bash
# parent.sh
childScript $param1 $param2&

Child script:

#!/bin/bash
# childScript.sh
param1=$1
param2=$2
someLinuxCommand $param1 $param2
out=$?
echo $out

If I execute childScript.sh with correct $param1 and $param2, $? will return 0. If $param1 and $param2 are incorrect, $? will return 1.

But no matter what $param1 and $param2 I send using parent.sh, $? always return 0. Why if I send incorrect $param1 and $param2 from parent.sh, $? in childScript.sh return 0?

Upvotes: 0

Views: 168

Answers (1)

Red Cricket
Red Cricket

Reputation: 10460

In your child script you are "returning" the result of echo which will always be 0. You should be using ...

exit $?

... instead. Or just leave that line out all together.

Here is an example that apes your scripts:

$ cat parent.sh
#!/bin/bash

p1=$1
p2='file'
./child.sh $p1 $p2

$ cat child.sh
#!/bin/sh

grep $1 $2
out=$?
echo $out

The child script will "grep" for the pattern in the "file". Here are the contents of the file "file". 

$ cat file
c.sh
file
in.txt
p.sh
bill

If grep find the pattern in the file grep will succeed thus setting $? to 0. But if grep does not find the pattern in the file grep will fail this setting $? to 1.

Here we run parent with a pattern of "bob"

$ ./parent.sh bob
1

grep did not find bob in thus sets $? to 1. echo outputs 1 and then sets $? to 0. 

$ echo $?
0

Let's fix the child.sh script to be:

$ cat child.sh
#!/bin/sh

grep $1 $2

and run parent.sh again:

$ ./parent.sh bob
$ echo $?
1

$ ./parent.sh bill
bill
$ echo $?
0

Upvotes: 1

Related Questions