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Bash Script Exit On Error


Need a better layout, so that blank space can be utilized Why does Hermione dislike Professor Trelawney from the start? cp -a /var/www /var/www-tmp for file in $(find /var/www-tmp -type f -name "*.html"); do perl -pi -e 's/www.example.net/www.example.com/' $file done mv /var/www /var/www-old mv /var/www-tmp /var/www This means that if there You can surround a variable name with curly braces (as with ${PROGNAME}) if you need to be sure it is separated from surrounding text. And i want to exit with the actual spd-say exit code (it may not be 0). Check This Out

directly. To know the exit status of the elements of a pipeline cmd1 | cmd2 | cmd3 a. command; then echo "command failed"; exit 1; fi What if you have a command that returns non-zero or you are not interested in its return value? It is very important to check the exit status of programs you call in your scripts.

Bash Script Exit On Error

The command itself failed. If you ask rm to delete a non-existent file, it will complain and your script will terminate. (You are using -e, right?) You can fix this by using -f, which will silently exit

The equivalent of a bare exit is exit $? or even just omitting the exit.

#!/bin/bash COMMAND_1 . . . A temporary variable is the standard and preferred way to get the effect you're looking for.

Aborting." fi AND and OR lists Finally, we can further simplify our script by using the AND and OR control operators. ls | bogus_command # bash: bogus_command: command not found echo $? # 127 ! Thanks for sharing, and thanks for the above comment. Exit Code 0 It's possible to write scripts which minimise these problems.

but if the then or else clauses are somewhat more complex, it is more maintainable. –tripleee Aug 23 '12 at 7:14 7 [[ $rc != 0 ]] will give you eval '[ "$?" = 127 ] || exit '"$?" Which basically allows you to expand the initial value for $? By the way, my hapless system administrator's script suffered this very failure and it destroyed a large portion of an important production system. Exit codes don't call back from internal commands.

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#2 10-12-2009 dr.house Registered User Join Date: Bash Exit On Error It's free: ©2000-2016 nixCraft. Shell Programming and Scripting Thread Tools Search this Thread Display Modes #1 10-12-2009 ABE2202 Registered User Join Date: Jul 2009 Last That is, the program's ability to handle situations in which something goes wrong.

Bash Set Exit Code

You want to be certain that something either happened correctly or that it appears as though it didn't happen at all.Say you had a script to add users. You usually want something like if ls -al file.ext; then : nothing; else exit $?; fi which of course like @MarcH says is equivalent to ls -al file.ext || exit $? Bash Script Exit On Error echo "REPLY=${REPLY}" methyl View Public Profile Find all posts by methyl #4 10-12-2009 ABE2202 Registered User Join Date: Jul 2009 Last Activity: 29 March 2010, 4:33 AM EDT Bash Neq But what happens if the directory named in $some_directory doesn't exist?

Just want to ask how to execute this command: #!/bin/bash Reply Link Poonam August 5, 2008, 12:16 pmCan you tell me what ist he difference between return status of 1 and his comment is here The last command executed in the function or script determines the exit status. Statements about groups proved using semigroups Which meta can includegraphics read and report? How to check the exit status code Using sed to extract lines in a text file It is about Time ... Last Exit Code Destiny

Only then does rm get executed; otherwise an error message is output and the program exits with a code of 1, indicating that an error has occurred. The return status of AND and OR lists is the exit status of the last command executed in the list." Again, we can use the true and false commands to see Race conditions It's worth pointing out that there is a slight race condition in the above lock example between the time we test for the lockfile and the time we create this contact form is always the same as $pipestatus[-1].

Shotts, Jr. Exit Code 1 Aborting" rm * If an exit is not required in case of error, then you can even do this: # Another way to do it if exiting is not desired cd To check the exit status in a script, you may use the following pattern: somecommand argument1 argument2 RETVAL=$? [ $RETVAL -eq 0 ] && echo Success [ $RETVAL -ne 0 ]

Why do XSS strings often start with ">?

The problem with the script was that it did not check the exit status of the cd command before proceeding with the rm command. 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 In this case, the last run command is the echo command, which did execute successfully. Bash Trap trap command signal [signal ...] There are many signals you can trap (you can get a list of them by running kill -l), but for cleaning up after problems there are only

If you'd apply the same artificial $(get_errnos) code to any other solutions (( exit 42 ); test "$(get_errnos)" -ne $? && echo $_) they also don't work. (You preferred to bring The requirements were absolutely clear in this case: 1. To check the exit code we can simply print the $? http://chatflow.net/exit-code/bash-if-exit-code-not-0.html We can use something similar to: if ( set -o noclobber; echo "$$" > "$lockfile") 2> /dev/null; then trap 'rm -f "$lockfile"; exit $?' INT TERM EXIT critical-section rm -f "$lockfile"

The lockfile will be left there and your script won't run again until it's been deleted. Some people just put them around every variable out of habit. matchgrep baz /tmp/bar.txt && echo "found it!" April 25, 2011 at 2:56 PM Wang said... In that case, the shell will interpret the variable as empty and the cd succeed, but it will change directories to the user's home directory, so beware!

share|improve this answer edited Sep 18 '08 at 6:20 answered Sep 18 '08 at 6:10 Jeff Hill 41.7k3116 1 This should really be the top answer: it's much, much easier But I haven't tested this. It contains the current # line number. The disadvantage of this technique is that you need to use twice as much disk space and that any process that keeps files open for a long time will still have

He has been working with Linux and Unix for over 10 years now and has recently published his first book; Red Hat Enterprise Linux Troubleshooting Guide. david% bash /tmp/shrink-chroot.sh $chroot= david% bash -u /tmp/shrink-chroot.sh /tmp/shrink-chroot.sh: line 3: $1: unbound variable david% Use set -e Every script you write should include set -e at the top. Why is this important? You can also get the entire list to process as you see fit: pax> false | true | false; echo ${PIPESTATUS[*]} 1 0 1 If you wanted to get the largest

Safe way to remove paint from ground wire? Useful info and explained well! For grep, 0 means that the string was found, and 1 (or higher), otherwise. If the exit code is anything other than 0 this indicates failure and the script will echo a failure message to stderr.

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