A shell command exit status.

stf92 · 10-28-2013, 05:51 PM

Hi: suppose I run

Code:

#!/bin/bash

cp ./* another/directory/
exit(0)

,

and I want to examine cp's exit status after the script completion. How can I do it? Of course, the same question goes for anyone of bash commands.

I guess I could use, too, a variable within the script, to save the exit status and then output it to console, but do not how to do it.

Firerat · 10-28-2013, 06:06 PM

$?
is the exit number of that last command/process

Code:

cp ./* another/directory/
cp_ExitCode=$?

.. work with ${cp_ExitCode} ..

another way, is list construct

Code:

cp ./* another/directory/ && echo "all went well" \
                          || echo "something went wrong"

advantage, easy
disadvantage, it is all or nothing
Most of the time that is perfectly fine,
but if you want to distinguish between exit codes ( instead of 0 and none-zero ) then $? gives you more options

http://www.tldp.org/LDP/Bash-Beginners-Guide/html/
http://www.tldp.org/LDP/abs/html/
http://mywiki.wooledge.org/BashGuide
http://www.gnu.org/software/bash/manual/bashref.html

The tldp stuff is great, however there are some nasty bad habits in it,
The mywiki.wooledge does a very good job of 'fixing' those habits

stf92 · 10-28-2013, 06:32 PM

Thanks a lot, and specially for your kind links. The guide by Garrels seems specially suited for me.

JJJCR · 10-29-2013, 02:38 AM

Quote:

Originally Posted by stf92

Hi: suppose I run

Code:

#!/bin/bash

cp ./* another/directory/
exit(0)

,

and I want to examine cp's exit status after the script completion. How can I do it? Of course, the same question goes for anyone of bash commands.

I guess I could use, too, a variable within the script, to save the exit status and then output it to console, but do not how to do it.

redirect the error to a file.

Quote:

cp ./* another/directory/ 2>>cp_error.log

stf92 · 10-29-2013, 11:04 AM

That seems like an elegant solution! Thanks.

rtmistler · 10-29-2013, 12:58 PM

What's wrong with either of:

Code:

#!/bin/bash

cp ./* another/directory/
exit $?

Or:

Code:

#!bin/bash

rc=`cp ./* another/directory/`

echo "Result of cp was $rc" >> mylogfile.txt;

exit $rc

Reason I say this is that the shell script returns the result of the cp, if that was the whole point and a calling function can further evaluate whether or not the script worked. I do either this or evaluate the outcome of system calls and shape my exit from the shell script accordingly because I call shell scripts from within a user application many times.