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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 in (1) :;; (*) echo $?;; esac All those options have the advantage that they are conforming to the POSIX standard. (Note: For illustration I used echo commands above; replace by Activate Hearthstone season chest cards? Within a script, an exit nnn command may be used to deliver an nnn exit status to the shell (nnn must http://waspsoft.com/bash-script/bash-script-capture-error-code.html

It contains the current # line number. The script you posted would have cp complaining about not having enough arguments - it requires at least two, and you have only given it one. –twalberg Jun 16 '14 at share|improve this answer edited Mar 17 '12 at 19:37 gatoatigrado 7,544445100 answered Jan 29 '09 at 22:07 Vladimir Graschenko add a comment| up vote 19 down vote If you just call Also the time where it is affected is reduced to the time between the two mvs, which should be very minimal, as the filesystem just has to change two entries in the

Shell Script Return Code

The problem with temporary variables is that they could shadow other variables, and to avoid that you must use long names, which is not good for code readability. Any script that is useful in some fashion will inevitably be either used in another script, or wrapped with a bash one liner. b. 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

  • share|improve this answer edited May 4 '12 at 13:19 answered May 4 '12 at 11:46 unwind 253k38330460 A command guaranteed to fail is wanted here: false. –chepner May 4
  • This would allot 50 valid codes, and make troubleshooting scripts more straightforward. [2] All user-defined exit codes in the accompanying examples to this document conform to this standard, except
  • By the way, my hapless system administrator's script suffered this very failure and it destroyed a large portion of an important production system.
  • Least Common Multiple Video displays in Star Wars Activate Hearthstone season chest cards?
  • I guess the problem is that invoking sudo as part of the test allows for sudo squashing the return of command in the first place and so skewing the test. –mikeserv
  • Why is this important?
  • COMMAND_LAST # Will exit with status of last command.

$? reads the exit status of the last command

Thanks, and fixed of course. –unwind May 4 '12 at 13:20 add a comment| up vote 2 down vote Some of answers rely on rewriting the code. What happens if I don't specify an exit code In Linux any script run from the command line has an exit code. And this is one of those cases where I suspect you're focusing on the wrong problem. Bash Script Error Output is always the same as $pipestatus[-1].

EDIT: I forgot to mention that i prefer a POSIX-complaint solution for better portability. Unix Exit Command In Shell Script Since exit code 1 signifies so many possible errors, it is not particularly useful in debugging.

There has been an attempt to systematize exit status numbers (see /usr/include/sysexits.h

In our example this isn't a problem as apache opens the files every request. Bash Script Error Log share|improve this answer edited Jun 14 '15 at 5:34 answered Jun 14 '15 at 1:03 mikeserv 37k341109 add a comment| up vote 8 down vote There are various options to handle asked 2 years ago viewed 381 times active 2 years ago Linked 215 bash: pipe output AND capture exit status Related 2882Can a Bash script tell which directory it is stored true echo "exit status of \"!

Unix Exit Command In Shell Script

I accepted a counter offer and regret it: can I go back and contact the previous company? And i want to exit with the actual spd-say exit code (it may not be 0). Shell Script Return Code Again, for readability you may want to use set -o errexit. Bash Script Error Checking Verbs of buttons on websites more hot questions question feed lang-sh about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life

There are other constructs you could use: command if [ "$?"-ne 0]; then echo "command failed"; exit 1; fi could be replaced with command || { echo "command failed"; exit 1; weblink Browse other questions tagged bash shell or ask your own question. directly. If the exit status is anything other than zero, then the program failed in some way. Bash Script Error Command Not Found

If you forget to check something, bash will do it or you. to a new value, 0 in this case: I see no reason for which the echo command have to fail. Hot Network Questions Can filling up a 75 gallon water heater tank without opening a faucet cause damage? navigate here When taking passengers, what should I do to prepare them?

If those answers do not fully address your question, please ask a new question. Bash Script Error Message The author of this document will not do fixups on the scripting examples to conform to the changing standard. 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!

List constructs allow you to chain commands together with simple && for and and || for or conditions.

What are the canonical white spaces? does not change the execution of the pipe. # Only the exit status changes. # =========================================================== # # Thanks, Stphane Chazelas and Kristopher Newsome.

Execution: $ ./tmp.sh Could not create file $ echo $? 1 Using exit codes on the command line Now that our script is able to tell both users and programs whether You can surround a variable name with curly braces (as with ${PROGNAME}) if you need to be sure it is separated from surrounding text. share|improve this answer answered Jun 13 '15 at 15:21 Scott 3,75821328 add a comment| up vote 0 down vote To answer your direct question, no, it's not possible to keep $? his comment is here 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

It's so standard that I would suggest abandoning (or rethinking) whatever reason you think you have for not wanting to use one; I highly doubt that it's worth the extra complexity Can Customs make me go back to return my electronic equipment or is it a scam? In this article, I explain several techniques for writing robust bash scripts. and where is this documented?

share|improve this answer edited Jul 7 at 15:50 answered May 5 '12 at 0:58 Dennis Williamson 167k42235305 Should be $(exit 42); echo "$?" –Elliot Chance Jul 14 '15 at And press return when you want to go forward –Hastur Jun 16 '14 at 11:51 please post some lines from copy_new_files.tmp. –Hastur Jun 16 '14 at 12:07 There's absolutely no grey area if you take the suggestion without unnecessarily introducing artificial nonsense. My purpose was to keep that value to skip the pause or to exit directly the next time that an error is found.

What other weird restrictions are going to be made up? –llua Jun 13 '15 at 18:03 1 @mikeserv; In case you missed it: I said: "There was a very first For instance, see my crc32 script. To add our own exit code to this script, we can simply use the exit command. This is Bash's way of giving functions a "return value." [1]

Following the execution of a pipe, a $? gives the exit status of