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Bash Exit On Error With Message

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I think the code got crippled while editing in WordPress. Please enable JavaScript to view the comments powered by Disqus. 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 OR read more like this:How do I find the exit status of a remote command executed via ssh?BASH Shell: How to run several commands in Sequence or all at onceHowTo: Debug http://waspsoft.com/bash-exit/bash-exit-error-message.html

bash error-handling multiplicity share|improve this question edited Oct 20 '12 at 1:23 asked Oct 19 '12 at 2:42 Ausghostdog 54117 Are you using /bin/bash or /bin/sh? –Alvin Wong Oct 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. If a program finishes successfully, the exit status will be zero. How to indicate you are going straight?

Bash Exit On Error Code

This can be fixed by using: if [ "$filename" = "foo" ]; When using $@ variable, you should always quote it or any arguments containing a space will be expanded in The list constructs use exit codes to understand whether a command has successfully executed or not. For example, if you failed to open /etc/passwd file you want to show an error message.

The old methodYou can write something as follows on bash using the if statement to

This script design even permits you to track and trace errors on single-line commands, which you almost never believed to fail. share|improve this answer answered Oct 22 '13 at 10:32 devnull 60.7k16102135 Ooh, I didn't know curly braces could do that. It's possible to write scripts which minimise these problems. Shell Script Exit Code Now, let's think about scripts, which usually run unattended, maybe invoked through cron.

Least Common Multiple My girlfriend has mentioned disowning her 14 y/o transgender daughter How to deal with a very weak student? Bash Exit Status Variable To experiment, try grep x at the command line without a file name and type in some lines with and without x in them, then ^D to exit. –jwpat7 Oct 19 When was this language released? How to deal with a really persuasive character?

I like your helper function :) –branquito Jul 6 '14 at 16:41 @branquito Yes. –konsolebox Jul 6 '14 at 16:44 add a comment| Your Answer draft saved draft Shell Script Error Handling If you use find and xargs together, you should use -print0 to separate filenames with a null character rather than new lines. You can print to stderr: [[ $TRESHOLD =~ ^[0-9]+$ ]] || { echo 1>&2 "Threshold must be an integer value!"; exit $ERRCODE; } –P.P. current community chat Unix & Linux Unix & Linux Meta your communities Sign up or log in to customize your list.

Bash Exit Status Variable

david% foo() { for i in $@; do printf "%s\n" "$i"; done }; foo bar "baz quux" bar baz quux david% foo() { for i in "$@"; do printf "%s\n" "$i"; The second use, ${1:-"Unknown Error"} means that if parameter 1 ($1) is undefined, substitute the string "Unknown Error" in its place. Bash Exit On Error Code exit "${2:-1}" ## Return a code specified by $2 or 1 by default. } [[ $TRESHOLD =~ ^[0-9]+$ ]] || error_exit "Threshold must be an integer value!" share|improve this answer answered Bash Throw Error Aborting" rm * If an exit is not required in case of error, then you can even do this: # Another way to do it if exiting is not desired cd

Exit status As you recall from previous lessons, every well-written program returns an exit status when it finishes. weblink If you look at exit codes in the context of scripts written to be used for the command line the answer is very simple. EDIT I know this will work, but how to suppress numeric arg required showing after my custom message? [[ $TRESHOLD =~ ^[0-9]+$ ]] || exit "Threshold must be an integer value!" It's not, if nothing goes wrong. Bash Set -e

For the error messange, I'm thinking of echoing something back like scriptname file_to_process > output_file. You could fix this using a backup and a trap, but you also have the problem that the site will be inconsistent during the upgrade too. The trap is completely circumvented by testing the directory for it's existence before deleting it. $ bash test.sh check if file exists: '/ksdjhfskdfkshd': failure, directory does not exist or is not http://waspsoft.com/bash-exit/bash-exit-with-error-message.html special variable to print the exit code of the script.

Also, note the inclusion of the LINENO environment variable which will help you identify the exact line within your script where the error occurred. #!/bin/bash # A slicker error handling routine Bash If Exit Code It contains the current # line number. Notice that we explicitly exit from the script at the end of trap command, otherwise the script will resume from the point that the signal was received.

share|improve this answer edited Oct 20 '12 at 18:59 answered Oct 19 '12 at 8:21 Ansgar Wiechers 84.7k1161101 An explanation of why this works would make this a better

Join them; it only takes a minute: Sign up Make Bash script exit and print error message if users invoke the script incorrectly up vote 3 down vote favorite 1 Script Here's the verbose output: $ sh -x traptest.sh ++ mktemp -d /tmp/test.XXXXXX + my_temp_dir=/tmp/test.CU3OxO + my_log_file=/tmp/test.CU3OxO/output.log + my_out_pipe=/tmp/test.CU3OxO/output.pipe + mkfifo /tmp/test.CU3OxO/output.pipe + exec + tee /tmp/test.CU3OxO/output.log + tee_pid=10753 + 3 traptest.sh: Testing for exit codes Earlier we used the $? Bash Error Message These commands have been designed so that they WILL fail for the sake of documentary purposes. #!/bin/bash # trap handler: print location of last error and process it further # function

I do not get any ether when mining Why did companions have such high social standing? You need to make sure that both the old and the new directories are moved to locations that are on the same partition so you can take advantage of the property 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. his comment is here 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

In a GNU C macro envSet(name), what does (void) "" name mean? You can check for files with files open by using lsof. To print any message like you want, you can use echo and then exit. [[ $TRESHOLD =~ ^[0-9]+$ ]] || \ { echo "Threshold must be an integer value!"; exit $ERRCODE; The second line shows the output from the trap handler, stating exactly WHERE the error occured (test.sh / line 22 / last exit status).

Never (as in NEVER) try to delete something without checking for it's existence first!