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I have a bash script file to process something.

control.sh :

c_command="echo 'Hello'; echo ', Stack Overflow';exit 9";
$c_command;
stat=$?;

if [ $stat -eq 0 ];then
      echo 'Do something....'
elif [ $stat -eq 9 ];then
      echo 'The system will be rebooting...';
else
      echo "..."
fi

I use the variable $c_command to execute the command, And I get the exit code is 0 not 9. If I paste it in command line is work perfect, But when I run in script is very bad.

Generally, when I execute "exit" command in script, then the script will be exit. And I just want the command done not the script and get the exit code from the command executed.

I solved this problem:

I put the code in $c_command to a script file and run it.

c_command="echo 'Hello'; echo ', Stack Overflow';exit 9";
echo "${c_command}" > tmp.sh;
/bin/bash tmp.sh;
stat=$?;

if [ $stat -eq 0 ];then
      echo 'Do something....'
elif [ $stat -eq 9 ];then
      echo 'The system will be rebooting...';
else
      echo "..."
fi
share|improve this question
When I run this script, the commands in $c_command run fine and there is an exit status of 0. You find that the whole script terminates instead? Are you actually running the script that you pasted here? – Michael Hoffman Apr 12 at 3:29
Yep, The $c_command should be return exit code is 9 not 0, cause I put the "exit 9" code in here. – Marc L. Apr 12 at 3:51

1 Answer

up vote 2 down vote accepted

Take a look at what your script actually prints, and that should give you a clue about why the exit status is 0:

$ bash ./control.sh
'Hello'; echo ', Stack Overflow';exit 9
Do something....

After c_command is expanded, the semicolons are not treated as command separators, but as literal characters. As a result, you have a single echo command that exits 0, not a pair of echo commands followed by an exit command.

Instead of storing code in a string, you should use a function:

c_command () {
    echo 'Hello'; echo ', Stack Overflow';return 9 
}
c_command
stat=$?
share|improve this answer
First, Thank you very much.. But the $c_command is not fixed, I get it through "grep" and "cut". – Marc L. Apr 12 at 3:47
@fozzmarc: Where do grep and cut come into it? Also, read BashFAQ #50:I'm trying to put a command in a variable, but the complex cases always fail! – Gordon Davisson Apr 12 at 4:04
Ok, I read the doc, and I know it. I get it from "#update#3322#1.0#/bin/bash 3322.sh#touch a.file;echo 'success';exit 9" string. – Marc L. Apr 12 at 4:24
Ok, now I solved this problem I put the script code into a file and run it... – Marc L. Apr 12 at 5:19

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