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Bash Script Check Error Status


bash shell share|improve this question edited Jul 31 '11 at 19:12 Cerin 16.3k36138273 asked Sep 18 '08 at 6:03 Mark Roddy 10.7k95161 1 I answered assuming you're using bash, but 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 Is my workplace warning for texting my boss's private phone at night justified? 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. Check This Out

Why does Windows show "This device can perform faster" notification if I connect it clumsily? Another example is rm. This site is not affiliated with Linus Torvalds or The Open Group in any way. share|improve this answer answered May 3 '15 at 22:12 niieani 9431017 add a comment| up vote 2 down vote Sorry that I can not make a comment to the first answer

Shell Script Check Error Code

Which is a useful feature when you're writing some common function that you will later source and use from other scripts. Skipping directly to level 4 How could banks with multiple branches work in a world without quick communication? My girlfriend has mentioned disowning her 14 y/o transgender daughter On THE other hand or on another hand? function directoryExists { cd $1 if [ $? = 0 ] then echo -e "${green}$1${NC}" else echo -e "${red}$1${NC}" fi } # EXE directoryExists "~/foobar" directoryExists "/www/html/drupal" The script works, but

check_exit_status "$?" Arguably, this is "cheating", since it makes a copy of $? 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 could then be removed and just used [ $? -ne 0 ]. –curtlee2002 May 21 '13 at 15:15 | show 2 more comments up vote 154 down vote If you want Bash Script Check If Root This can be fixed by using: if [ "$filename" = "foo" ]; When using [email protected] variable, you should always quote it or any arguments containing a space will be expanded in

Also, just to be clear, command won't test for the location of any arguments to sudo - so it is only sudo - and nothing it invokes - which is relevant I use this construct in scripts where i want to provide alternatives for the same command. Why did companions have such high social standing? This becomes more important as your programs get more complex and you start having scripts launching other scripts, etc.

Dennis numbers 2.0 Force Microsoft Word to NEVER auto-capitalize the name of my company Do COB LEDs usually need electrically insulating from the heatsink? Bash Script Check If Directory Exists 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 $? Revised. Testing for exit codes Earlier we used the $?

Bash Script If Error Code

changes things: > cat tst.sh #!/bin/bash ping nosuchhost [ $? -ne 1 ] && exit $? > ./tst.py ping: unknown host nosuchhost 0 Yes, the 2nd reference to $? special variable in bash. Shell Script Check Error Code Problem with using pause and onslide in one frame How to extrude a face parallel to another? Bash Script Exit Status ls | bogus_command # bash: bogus_command: command not found echo $? # 0 # Note that the !

IMHO it's better to stick to a consistent method which works in other cases (and can also help with the code readability). –Dan Cornilescu Jun 13 '15 at 15:46 4 his comment is here I was hoping to use this, something portable-ish though –ThorSummoner Jun 21 '15 at 4:14 this should be the accepted answer –user22866 Aug 30 '15 at 23:29 There are several things you can do to prevent errors in these situations. How rich can one single time travelling person actually become? Bash Script Check If Command Exists

  • See my answer.
  • An AND list has the form command1 && command2 command2 is executed if, and only if, command1 returns an exit status of zero.
  • add_to_passwd $user cp -a /etc/skel /home/$user chown $user /home/$user -R There could be problems if you ran out of diskspace or someone killed the process.
  • Allen 53228 That also fixes (unless xpg_echo is on) the issues when filenames contain backslash characters. –Stéphane Chazelas Oct 22 '13 at 14:28 add a comment| up vote 4
  • is updated after each command exits.
  • Similarly, put $1 inside the quotes in the echo command. –Gordon Davisson Mar 4 '11 at 16:01 edited, thanks for the advice ! –krtek Mar 4 '11 at 16:05
  • environment variable. $?
  • It seems like exit codes are easy for poeple to forget, but they are an incredibly important part of any script.
  • If the exit code is anything other than 0 this indicates failure and the script will echo a failure message to stderr.
  • The list constructs use exit codes to understand whether a command has successfully executed or not.

There is a little trick that can be used to fix this: run the inner command in background, and then immediately wait for it. You can read more about parameter expansion in the bash man page under the topic "EXPANSIONS". Aborting." 1>&2 exit 1 fi Here we check to see if the cd command is successful. this contact form fi for most cases, it's easier to use the && construct to chain commands that need to depend on each other.

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 Bash Script Check For Arguments Unix & Linux Stack Exchange works best with JavaScript enabled current community chat Unix & Linux Unix & Linux Meta your communities Sign up or log in to customize your list. If not, why?

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Aborting." fi AND and OR lists Finally, we can further simplify our script by using the AND and OR control operators. command1; then share|improve this answer edited Sep 23 at 17:57 answered Jul 10 '15 at 18:37 dimo414 20.2k774118 2 Thanks for the if ! I once had a Unix system administrator who wrote a script for a production system containing the following 2 lines of code: # Example of a really bad idea cd $some_directory Bash Script Check File Size To add our own exit code to this script, we can simply use the exit command.

Linux is a registered trademark of Linus Torvalds. david% foo() { for i in [email protected]; do printf "%s\n" "$i"; done }; foo bar "baz quux" bar baz quux david% foo() { for i in "[email protected]"; do printf "%s\n" "$i"; Using -e gives you error checking for free. http://gatoisland.com/bash-script/bash-script-set-error.php You might need to save the value of $?

No need to repeat your (IMO wrong) opinion here, or start another iteration of the dispute. –Janis Jun 14 '15 at 7:04 1 @mikeserv; The expansion side effects in the but if the then or else clauses are somewhat more complex, it is more maintainable. –tripleee Aug 23 '12 at 7:14 6 [[ $rc != 0 ]] will give you Convince people not to share their password with trusted others In a GNU C macro envSet(name), what does (void) "" name mean? This variable will print the exit code of the last run command.

Ask Ubuntu works best with JavaScript enabled David Pashley.com Home Articles Dial On Demand with WVDial Writing Robust Bash Shell Scripts PostgreSQL User Administration Network Troubleshooting Becoming a X.509 Certificate Authority In this article, I explain several techniques for writing robust bash scripts. The lockfile will be left there and your script won't run again until it's been deleted. Natural construction Using Map to convert Feet + Inches to Inches in a List of Lists A simple visual puzzle to die for Meaning of Guns and ghee How to deal

This site is not affiliated with Linus Torvalds or The Open Group in any way. share|improve this answer answered Jun 13 '15 at 15:00 Dan Cornilescu 77616 What value does your Python script add to this answer? –G-Man Jun 13 '15 at 15:27 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 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.

IBM documentation says otherwise. –Patrick James McDougle Aug 12 '14 at 20:56 add a comment| up vote 13 down vote [ $? -eq 0 ] || exit $?; # exit for Hot Network Questions How to handle spending money for extended trip to Europe? exit / exit status

#!/bin/bash echo hello echo $? # Exit status 0 returned because command executed successfully. Let foo be a function that does not "return" (echo) a value, but it sets the exit code as usual.

It contains the current # line number. true\" = $?" # 1 # Note that the "!" needs a space between it and the command. # !true leads to a "command not found" error # # The '!' and $_ references. Password Protected Wifi, page without HTTPS - why the data is send in clear text?

I would like to do something like this: echo "trying stuff" try { command1 command2 command3 } And at any point, if any command fails, drop out and echo out the Toggle navigation Benjamin Cane Home Archive RSS Twitter Mail Feed Understanding Exit Codes and how to use them in bash scripts When writing a script that calls other commands, how do This happens for instance in cmd | head -1 you might observe a 141 (or 269 with ksh93) exit status of cmd1, but it's because cmd was interrupted by a SIGPIPE

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