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Bash Script Capture Error Code


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 Finally, you can also use this in the script that uses scp, since it works regardless of the command you're using. function directoryExists { # was: do the cd in a sub-shell so it doesn't change our own PWD # was: if errmsg=$( cd -- "$1" 2>&1 ) ; then if [ Beware that set -e doesn't always kick in. this contact form

Unix & Linux Stack Exchange works best with JavaScript enabled Toggle navigation Benjamin Cane Home Archive RSS Twitter Mail Feed Understanding Exit Codes and how to use them in bash The code is this: #! /bin/bash echo "Submit Lab$1? \c" read choice if [ $choice = "y" ]; then echo "Sending to Prof's dropbox..." cp -r /path/to/lab$1 /path/to/dropbox else echo "Submission It should work in all POSIX-compatible shells if you remove local keywords, i.e. The two lines change the working directory to the name contained in $some_directory and delete the files in that directory.

Bash Script Check Error Code

Still need to catch the error output but I believe I know where I need to go to figure that out on my own, so this question is answered as far The benefit of using -e is that it prevents errors snowballing into serious issues when they could have been caught earlier. UNIX is a registered trademark of The Open Group.

It is better :) –Sreeraj Feb 13 '15 at 7:02 add a comment| up vote 3 down vote I capture error like this . ${file} 2>&1 | { read -d "\0" Thanks for editing. –JRFerguson Oct 22 '13 at 13:36 add a comment| up vote 0 down vote Actually for your case I would say that the logic can be improved. 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 Bash Script Regex Capture On THE other hand or on another hand?

true !true # No error this time, but no negation either. # It just repeats the previous command (true). # =========================================================== # # Preceding a _pipe_ with ! Bash Exit Script With Error Code if failing_command, failing_command || fallback). Thanks! –Skippr Jan 17 '12 at 2:18 1 If you don't mind my asking, what does the integer after "exit" do? –Skippr Jan 17 '12 at 2:38 2 The 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

What to tell to a rejected candidate? Bash Script Catch Error How to extrude a face parallel to another? Using -e gives you error checking for free. Thanks for the review! =) –skozin Jan 11 at 17:20 @sam.kozin I forgot to write in my previous comment: you may want to post this on Code Review and

Bash Exit Script With Error Code

For example, false | true will be considered to have succeeded. Least Common Multiple Now I know my ABCs, won't you come and golf with me? Bash Script Check Error Code if [ -d "$1" ] then printf "${green}${NC}\\n" "$1" cd -- "$1" else printf "${red}${NC}\\n" "$1" fi But if your purpose is to silence the possible errors then cd -- "$1" Bash Script Capture Output In particular you should use quotes around variables.

On POSIX systems the standard convention is for the program to pass 0 for successful executions and 1 or higher for failed executions. weblink Assuming I have this question answered, can I apply the solutions to scp exactly the same way? 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 The Linux Documentation Project has a pretty good table of reserved exit codes and what they are used for. Bash Script Capture Output From Command

The list constructs use exit codes to understand whether a command has successfully executed or not. share|improve this answer edited Jan 11 at 17:11 answered Oct 23 '13 at 16:19 Gilles 369k666681119 Recently I experimented a little and discovered a convenient way of fixing || You can surround a variable name with curly braces (as with ${PROGNAME}) if you need to be sure it is separated from surrounding text. navigate here The difference between a good program and a poor one is often measured in terms of the program's robustness.

Why is this important? Bash Script Error Command Not Found In that case, the cd command will fail and the script executes the rm command on the current working directory. I didn't know about the if [ -d $1 ] that's exactly what I needed.

ls | bogus_command # bash: bogus_command: command not found echo $? # 0 # Note that the !

Thanks! The lockfile will be left there and your script won't run again until it's been deleted. Why don't most major game engines use gifs for animated textures? Bash Script Error Log Execution: $ ./tmp.sh Could not create file Providing your own exit code While the above revision will provide an error message if the touch command fails, it still provides a 0

bash shell terminal share|improve this question asked Feb 25 '14 at 9:09 Lee Probert 2,35152335 Why not an if else ? –Thomas Ayoub Feb 25 '14 at 9:11 will contain the exit status of the last command executed. 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 his comment is here COMMAND_LAST # Will exit with status of last command.

There are several things you can do to prevent errors in these situations. Using Map to convert Feet + Inches to Inches in a List of Lists Were slings used for throwing hand grenades? How's the CMD trip bonuses from extra legs work? In a GNU C macro envSet(name), what does (void) "" name mean?

For example, when you create a directory, if the parent directory doesn't exist, mkdir will return an error. How rich can one single time travelling person actually become? Instead of cd and then check if it exists, check if it exists then go into the directory. 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

We can also use this variable within our script to test if the touch command was successful or not. special variable as follows: if [ "$?" -ne "0" ]; then echo "Submission failed" exit 1 fi echo "Submission successful." Additionally, if you want a clean prompt, you can redired stderr If the exit status is anything other than zero, then the program failed in some way. I like the try/catch so much. –erm3nda Jul 24 '15 at 17:51 @erm3nda Glad to hear that!

So basically, something like: echo "Submit lab$1?" read choice echo "Send to Prof's dropbox" cp -rv /path/to/lab$1 /path/to/dropbox if [ cp has errors ] echo "Submission An AND list has the form command1 && command2 command2 is executed if, and only if, command1 returns an exit status of zero. asked 3 years ago viewed 40901 times active 13 days ago Linked 9 Redirect stdout over ssh Related 2How do I execute a remote shell script over SSH and be prompted The most common error would probably be "cannot stat blah: no such file or directory." I would like to catch that error, and simply say "Submission failed." EDIT #2: jcollado's answer

There is a little trick that can be used to fix this: run the inner command in background, and then immediately wait for it. In the bash, instead, only the command in question will exit with an exit code greater than 0, indicating that error state.

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