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Bash Check Return Code Script


If the exit code is anything other than 0 this indicates failure and the script will echo a failure message to stderr. Exit codes don't call back from internal commands. bash shell share|improve this question edited Jul 31 '11 at 19:12 Cerin 17.1k38144282 asked Sep 18 '08 at 6:03 Mark Roddy 11.2k95261 2 I answered assuming you're using bash, but rollback() { del_from_passwd $user if [ -e /home/$user ]; then rm -rf /home/$user fi exit } trap rollback INT TERM EXIT add_to_passwd $user cp -a /etc/skel /home/$user chown $user /home/$user -R his comment is here

Join them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the true echo "exit status of \"! behind the scenes; that's what they do. parameter, using if to check if it's non-zero, which is not very elegant and a bit hard to read: # Bad practice grep -q regex options if (($? > 0)); then

Bash Set Exit Code

What happens if I don't specify an exit code In Linux any script run from the command line has an exit code. to get the exit status of the previously executed command. Is it possible to do that without a temporary variable? in the check_exit_status argument list.

the rest of the script goes here # function catch_errors() { # do whatever on errors # # echo "script aborted, because of errors"; exit 0; } share|improve this answer answered Fortunately bash provides you with set -u, which will exit your script if you try to use an uninitialised variable. This may seem a little awkward, and it is.  (That sometimes happens when you impose arbitrary constraints on problems.)  This may seem inflexible, but it isn't.  You can make check_exit_status more Last Exit Code Destiny Unfortunately shell scripts are full of subtle effects which result in scripts failing in unusual ways.

echo exit 113 # Will return 113 to shell. # To verify this, type "echo $?" after script terminates. # By convention, an 'exit 0' indicates success, #+ while a non-zero To print? Using exit codes in your bash scripts While removing the echo command from our sample script worked to provide an exit code, what happens when we want to perform one action That is, the program's ability to handle situations in which something goes wrong.

Another example to clarify further: spd-say "$@" [ $? -ne 127 ] && exit $? Exit Code 0 For example, to determine whether a particular regular expression regex was present somewhere in a file options, we might apply grep(1) with its POSIX -q option to suppress output and just If the touch command fails however, we will print a failure message to stderr and exit with a 1 value which indicates failure. Verbatim copying and distribution of this entire article is permitted in any medium, provided this copyright notice is preserved.

Bash Script Exit On Error

But what happens if the directory named in $some_directory doesn't exist? By not defining proper exit codes you could be falsely reporting successful executions which can cause issues depending on what the script does. Bash Set Exit Code echo $? # Non-zero exit status returned -- command failed to execute. Bash Neq So to check the exit status, we could write the script this way: # Check the exit status cd $some_directory if [ "$?" = "0" ]; then rm * else echo

Program defensively - expect the unexpected Your script should take into account of the unexpected, like files missing or directories not being created. this content Sample Output: 2 According to ls man page - exit status is 0 if OK, 1 if minor problems, 2 if serious trouble. If a program finishes successfully, the exit status will be zero. A temporary variable is the standard and preferred way to get the effect you're looking for. Exit Bash Shell

If you look at exit codes in the context of scripts written to be used for the command line the answer is very simple. set +e command1 command2 set -e On a slightly related note, by default bash takes the error status of the last item in a pipeline, which may not be what you return exit code. - Do you get that? - You changed that requirement arbitrarily to just make up an argument. –Janis Jun 14 '15 at 8:27 | show 8 more comments http://blackplanetsupport.com/exit-code/bash-return-code.html Combined with OR the bash should only invoke exit, if the previous command fails.

more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed Bash Exit On Error An error exit function Since we will be checking for errors often in our programs, it makes sense to write a function that will display error messages. Previous | Contents | Top | Next © 2000-2017, William E.

david% touch "foo bar" david% find | xargs ls ls: ./foo: No such file or directory ls: bar: No such file or directory david% find -print0 | xargs -0 ls ./foo

You can use exit status in shell scripting too. E.g., I would like to do: command -p sudo ... [ $? -ne 1 ] && exit $? unaltered. Exit Code 1 For example, false | true will be considered to have succeeded.

Negating a condition using !

true # The "true" builtin. comments powered by Disqus Benjamin is a Systems Architect working in the financial services industry focused on platforms that require Continuous Availability. On POSIX systems the standard convention is for the program to pass 0 for successful executions and 1 or higher for failed executions. check over here ls /eeteec echo $?

Especially if that script is used for the command line. Improving the error exit function There are a number of improvements that we can make to the error_exit function.