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Bash Script Quit If Error


Don't let this happen to you! rm -rf $chroot/usr/share/doc If you ran the script above and accidentally forgot to give a parameter, you would have just deleted all of your system documentation rather than making a smaller and you want to be dead certain it starts again at the end, even if there is some runtime error. 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. http://onlinetvsoftware.net/bash-script/bash-script-error-127.php

So sayeth the Shepherd Were slings used for throwing hand grenades? This variable will print the exit code of the last run command. Written by Benjamin Cane on 2014-09-02 14:45:00| 4 min read Sponsored by Lately I've been working on a lot of automation and monitoring projects, a big part of these projects are echo $? # Non-zero exit status returned -- command failed to execute.

Bash Exit Script On Error

In our example this isn't a problem as apache opens the files every request. Shotts, Jr. Execution: $ ./tmp.sh touch: cannot touch '/root/test': Permission denied created file $ echo $? 0 As you can see after running the ./tmp.sh command the exit code was 0 which indicates But what happens if the directory named in $some_directory doesn't exist?

  1. special variable to print the exit code of the script.
  2. Actions such as printing to stdout on success and stderr on failure.
  3. Unfortunately it means you can't check $?
  4. In the following example, the 3rd line is not executed because the script exits at the call to false.
  5. You might write: for file in $(find /var/www -type f -name "*.html"); do perl -pi -e 's/www.example.net/www.example.com/' $file done Now if there is a problem with the script you could have
  6. Again, for readability you may want to use set -o errexit.
  7. If the exit code of ./tmp.sh is 1 however, the commands within the parenthesis will be executed next.
  8. echo "Example of error with line number and message" error_exit "$LINENO: An error has occurred." The use of the curly braces within the error_exit function is an example of parameter expansion.
  9. line), but for me it does not work as expected with bash v3.2.57 on Mac OS X.

The original script did not || the for loop. –RobertL Nov 6 '15 at 8:06 I just noticed I hadn't shown the set -o errexit command in my example share|improve this answer edited Aug 7 '15 at 7:10 flying sheep 2,96722245 answered Sep 4 '09 at 9:53 Michael Foukarakis 20.5k35089 42 0 isn't good status to exit with if This becomes more important as your programs get more complex and you start having scripts launching other scripts, etc. Bash If Exist Browse other questions tagged bash shell-script or ask your own question.

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 add a comment| 1 Answer 1 active oldest votes up vote 237 down vote accepted Maybe you want set -e: http://www.davidpashley.com/articles/writing-robust-shell-scripts.html#id2382181 share|improve this answer answered Aug 13 '10 at 6:50 Alok 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 An OR list has the form command1 || command2 command2 is executed if, and only if, command1 returns a non-zero exit status.

That is, the program's ability to handle situations in which something goes wrong. Bash Exit 0 Is there a good way to get from Levoča to Lviv? I like to include the name of the program in the error message to make clear where the error is coming from. To help explain exit codes a little better we are going to use a quick sample script.

Bash Script If Exit Code

for major in {1..4}; do for minor in {0..99}; do for patchlevel in {0..99}; do tarball="linux-${major}-${minor}-${patchlevel}.tar.bz2" curl -q "http://kernel.org/path/to/$tarball" -o "$scratch/$tarball" || true if [ -f "$scratch/$tarball" ]; then tar jxf Force Microsoft Word to NEVER auto-capitalize the name of my company On THE other hand or on another hand? Bash Exit Script On Error does not change the execution of the pipe. # Only the exit status changes. # =========================================================== # # Thanks, Stphane Chazelas and Kristopher Newsome.

This site is not affiliated with Linus Torvalds or The Open Group in any way. http://onlinetvsoftware.net/bash-script/bash-script-bus-error.php Usually a well written bash script will work if you add set -e at the start and the addition works as an automated sanity check: abort the script if anything goes In this lesson, we're going to look at handling errors during the execution of your scripts. If you later add a new in-script exit, it's easy to forget to include the removal - potentially creating mysterious heisenleaks. Bash If Status

Execution: $ ./tmp.sh touch: cannot touch '/root/test': Permission denied $ echo $? 1 As you can see, since the last command run was touch the exit code reflects the true status The arithmetic expression expr2 is then evaluated repeatedly until it evaluates to zero. COMMAND_LAST # Will exit with status of last command. his comment is here Hope that explains everything.

true\" = $?" # 1 # Note that the "!" needs a space between it and the command. # !true leads to a "command not found" error # # The '!' Exit Bash Shell How can I get the entire script to exit if this curl statement fails? 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.

You can see this work with the following: [me] $ true; echo $? 0 [me] $ false; echo $? 1 The true and false commands are programs that do nothing except

Aborting." 1>&2 exit 1 fi Here we check to see if the cd command is successful. The advantage of this over the set -e solution is that the script doesn't exit silently when a line fails, and can tell you what the problem is. Script: #!/bin/bash touch /root/test 2> /dev/null if [ $? -eq 0 ] then echo "Successfully created file" exit 0 else echo "Could not create file" >&2 exit 1 fi With the Bash Exit Script From Function Skeletal formula for carbon with two double bonds How to indicate you are going straight?

as bash will never get to the checking code if it isn't zero. See also Exit Codes With Special Meanings. In a GNU C macro envSet(name), what does (void) "" name mean? weblink share|improve this answer edited Sep 12 '14 at 15:22 answered Sep 12 '14 at 14:56 kavadias 30148 add a comment| up vote 3 down vote Instead of if construct, you can

share|improve this answer answered Nov 6 '15 at 7:51 RobertL 3,655119 set -e is more subtle than that. However, it seems silly to run the tests if compiling the code fails in the first place, in which case I'll just abort the tests. Will the medium be able to last 100 years?