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Bash Script Return Error


I accepted a counter offer and regret it: can I go back and contact the previous company? UNIX is a registered trademark of The Open Group. That is, the program's ability to handle situations in which something goes wrong. For example, if (( 5 * $b > 53 )). navigate here

About your wish: I expected such safe behavior from a sensible programming language... It seems like exit codes are easy for poeple to forget, but they are an incredibly important part of any script. But what happens if the directory named in $some_directory doesn't exist? asked 5 years ago viewed 51706 times active 10 months ago Get the weekly newsletter!

Bash Script Return Error Message

How does Gandalf get informed of Bilbo's 111st birthday party? 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 I'm looking for a way to make it always abort on syntax errors. –imz -- Ivan Zakharyaschev Jul 8 '13 at 20:30 add a comment| up vote 0 down vote First, If the exit code is anything other than 0 this indicates failure and the script will echo a failure message to stderr.

Here, $?will be the exit status of this command sudo apt-get install --assume-yes [email protected] else ## Else, return the exit value of the first apt-get return $ret fi } The general Skeletal formula for carbon with two double bonds How to handle spending money for extended trip to Europe? You can check for files with files open by using lsof. Bash Script Return Exit Code In that case, the cd command will fail and the script executes the rm command on the current working directory.

But my question still makes sense. With Bash scripts, if the exit code is not specified in the script itself the exit code used will be the exit code of the last command run. Commands whose status is tested by a conditional (such as if, && or ||) do not terminate the script (otherwise the conditional would be pointless). How to pluralize "State of the Union" without an additional noun?

Previous | Contents | Top | Next © 2000-2016, William E. Bash Script Return Value From Command Thanks –MountainX Jul 7 '13 at 19:12 @MountainX see updated answer. share|improve this answer edited Jul 8 '13 at 19:05 answered Jul 8 '13 at 18:48 gniourf_gniourf 1,291412 I meant the absence of such feature is a problem. The second use, ${1:-"Unknown Error"} means that if parameter 1 ($1) is undefined, substitute the string "Unknown Error" in its place.

  1. share|improve this answer answered Jul 8 '13 at 16:42 ahilsend 60155 2 Now your function definition is parsed and evaluated, and it fails. –tripleee Jul 8 '13 at 17:00
  2. This tells bash that it should exit the script if any statement returns a non-true return value.
  3. This will save more typing and promote laziness. # An error exit function function error_exit { echo "$1" 1>&2 exit 1 } # Using error_exit if cd $some_directory; then rm *
  4. what is the difference between \twocolumn and \documentclass[twocolumn]{book} Can Customs make me go back to return my electronic equipment or is it a scam?
  5. Meaning of Guns and ghee Rosa Parks is a [symbol?] for the civil rights movement?
  6. trap : 0 echo >&2 ' ************ *** DONE *** ************ ' share|improve this answer answered Mar 5 '14 at 15:43 supercobra 2,90242737 Why the DONE message to stderr?
  7. On Unix and Linux systems, programs can pass a value to their parent process while terminating.
  8. My question is not about set -e, it's about the unsafety of bash if it can't be made to abort on sytax errors.

Exit Bash Script Early

GTIN validation How would family relationships change if legal system uses collective punishment? Unix & Linux Stack Exchange works best with JavaScript enabled current community blog chat Super User Meta Super User your communities Sign up or log in to customize your list. Bash Script Return Error Message Probably returning some kind of non-zero value should work. Bash Script Return Value store the function in a shell script, and invoke e.g.

The last command executed in the function or script determines the exit status. http://onlinetvsoftware.net/bash-script/bash-script-tar-error.php The benefit of using -e is that it prevents errors snowballing into serious issues when they could have been caught earlier. The difference between a good program and a poor one is often measured in terms of the program's robustness. Problem? Bash Script Carriage Return

Convince people not to share their password with trusted others Meaning of Guns and ghee Skeletal formula for carbon with two double bonds Is 8:00 AM an unreasonable time to meet Is that right? So what can you do about it? his comment is here below the cmake call to exit the function with the same exit code as cmake, and add return 1 below the echo call to exit with 1, which is non-zero and

PROGNAME=$(basename $0) function error_exit { # ---------------------------------------------------------------- # Function for exit due to fatal program error # Accepts 1 argument: # string containing descriptive error message # ---------------------------------------------------------------- echo "${PROGNAME}: ${1:-"Unknown Bash Script Return True Can filling up a 75 gallon water heater tank without opening a faucet cause damage? Be prepared for spaces in filenames Someone will always use spaces in filenames or command line arguments and you should keep this in mind when writing shell scripts.

The above command will execute the ./tmp.sh script, and if the exit code is 0 the command echo "bam" will be executed.

Using if, we could write it this way: # A better way if cd $some_directory; then rm * else echo "Could not change directory! 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. That's the intended behavior. Bash Script Return From Function exit / exit status

#!/bin/bash echo hello echo $? # Exit status 0 returned because command executed successfully.

Using -e gives you error checking for free. It is also important that your scripts return a meaningful exit status when they finish. special variable to print the exit code of the script. weblink Limit involving exponentials and arctangent without L'Hôpital Convince people not to share their password with trusted others Meaning of Guns and ghee How to make different social classes look quite different?

Exit and Exit Status... I know I have, many times. more hot questions question feed lang-bsh about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation Sorry about that. –Daniel Beck♦ Dec 26 '11 at 9:50 add a comment| You must log in to answer this question.

This may help when using test or && or ||. –mouviciel Dec 7 '10 at 21:27 4 To expand on mouviciel's comment: in shell scripts, 0 always means success, and perhaps this must be reported as a bug/wish to bash developers) More experiments if makes no difference. For example, false | true will be considered to have succeeded. Improving the error exit function There are a number of improvements that we can make to the error_exit function.

up vote 5 down vote favorite 1 I was tasked to create an automated server hardening script and one thing that they need is a report of all the output of Can Customs make me go back to return my electronic equipment or is it a scam? Second, the ${a[#]} is weird and its is why is giving errors... Why is this important?

If you would like this to fail, then you can use set -o pipefail to make it fail. Should indoor ripened tomatoes be used for sauce? The lockfile will be left there and your script won't run again until it's been deleted. as bash will never get to the checking code if it isn't zero.

The fix is to use: if [ ! -e $lockfile ]; then trap "rm -f $lockfile; exit" INT TERM EXIT touch $lockfile critical-section rm $lockfile trap - INT TERM EXIT else I guess adding return $? Or, without set -e: bash -n "$0" || exit –Daniel S Aug 27 '15 at 9:56 add a comment| up vote 4 down vote You are probably mislead about the genuine I have to say this doesn't feel very robust, but if it works for you, perhaps it is acceptable.