Use output of command as exit code

bashexit codegit

For my Continuous Integration scripts I want to check if the git branch is not in sync with the master branch. Therefore I use

git rev-list --left-right --count master...my-branch-name

It will return sth. like

1    3

(3 commits ahead of master, 1 behind)

Adding | cut -f1 will give me only the first number (commits behind master).

Now I want to exit the script just with that number because 0 commits behind is success, all other should give an error.

How can I do that? I tried

exit 'git rev-list --left-right --count master...my-branch-name | cut -f1'

but this raises

/bin/bash: line 66: exit: git rev-list –left-right –count master…my-branch-name | cut -f1: numeric argument required

Is there a best practice for this?

Best Answer

Simply change your line:

exit 'git rev-list --left-right --count master...my-branch-name | cut -f1'

to:

exit `git rev-list --left-right --count master...my-branch-name | cut -f1`

Anything between the ` quotation marks will be executed and returned to the bash script, so you can do whatever you want with it, including assigning it to a variable.

Related Solutions

Getting ROBOCOPY to return a “proper” exit code

As per here, Robocopy has the following exit code bits that make up the exit code:

0×10 Serious error. Robocopy did not copy any files. This is either a usage error or an error due to insufficient access privileges on the source or destination directories.

0×08 Some files or directories could not be copied (copy errors occurred and the retry limit was exceeded). Check these errors further.

0×04 Some Mismatched files or directories were detected. Examine the output log. Housekeeping is probably necessary.

0×02 Some Extra files or directories were detected. Examine the output log. Some housekeeping may be needed.

0×01 One or more files were copied successfully (that is, new files have arrived).

0×00 No errors occurred, and no copying was done. The source and destination directory trees are completely synchronized.

Just add if/else statements that EXIT /B 0 when the return value is 1 or maybe 0, and EXIT /B 1 otherwise. Even if files might have been copied, there's something wrong that would need manual intervention.

Linux – exit code 128, what’s the reason

There is nothing within Bash documentation that says 128 is the required invalid exit code.

Bash itself returns the exit status of the last command executed, unless a syntax error occurs, in which case it exits with a non-zero value.

The last command is the bash builtin exit (from man page)

exit [n]

Cause the shell to exit with a status of n. If n is omitted, the exit status is that of the last command executed.

Checked specification for WEXITSTATUS.

WEXITSTATUS(stat_val)

If the value of WIFEXITED(stat_val) is non-zero, this macro evaluates to the low-order 8 bits of the status argument that the child process passed to _exit() or exit(), or the value the child process returned from main().

So exit is restricted to an 8 bit integer ( 0 - 255 ), so -1 would be 255. Exit only understands an integer argument and not floats, so it's likely kicking out a default -1.

bash$ echo $BASH_VERSION
4.1.10(4)-release

bash$ exit foo
exit
bash: exit: foo: numeric argument required
$ echo $?    
255

bash$ exit 2
exit
$ echo $?
2

bash$ exit -2
exit
$ echo $?
254

Best Answer

Related Solutions

Getting ROBOCOPY to return a “proper” exit code

Linux – exit code 128, what’s the reason

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