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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. test.sh: line 34: rmdiir: command not found test.sh: line 45: exit status of last command: 127 failed: directory not deleted. Why promote it by giving it as an example? –Charles Duffy Apr 8 '13 at 17:28 add a comment| up vote 11 down vote I prefer something really easy to call. 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; http://sovidi.com/bash-script/bash-script-bus-error.php

Any other value means something went wrong. Instead of cd and then check if it exists, check if it exists then go into the directory. Aborting." 1>&2 exit 1 fi Here we check to see if the cd command is successful. This is an excellent way to debug a script.

Bash Script Error Command Not Found

command; then echo "command failed"; exit 1; fi What if you have a command that returns non-zero or you are not interested in its return value? up vote 5 down vote favorite 1 I made the following script: # !/bin/bash # OUTPUT-COLORING red='\e[0;31m' green='\e[0;32m' NC='\e[0m' # No Color # FUNCTIONS # directoryExists - Does the directory exist? So, here's my hint: file content: lib.trap.sh lib_name='trap' lib_version=20121026 stderr_log="/dev/shm/stderr.log" # # TO BE SOURCED ONLY ONCE: # ###~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~## if test "${g_libs[$lib_name]+_}"; then return 0 else if test ${#g_libs[@]} == 0;

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. It does this displaying a # given error message, and exiting with an error code. We can use something similar to: if ( set -o noclobber; echo "$$" > "$lockfile") 2> /dev/null; then trap 'rm -f "$lockfile"; exit $?' INT TERM EXIT critical-section rm -f "$lockfile" Bash Script Error Message An advantage is that you now have a backup before you made your changes in case you need to revert. © 2013 Company Name Advanced Bash-Scripting Guide: Prev

What could cause the throttle to stick in my Ford Ranger? Bash Script Error Check The trick is to run the inner command in background, and then immediately wait for it. is_shell_attribute_set e; then set -e e_was_set=0 fi "$cmd" "[email protected]" & wait $! || { exit_code=$? } if [ "$e_was_set" = 0 ] && is_shell_attribute_set e; then set +e fi if [ You can surround a variable name with curly braces (as with ${PROGNAME}) if you need to be sure it is separated from surrounding text.

if [ "$?" != "0" ]; then echo "[Error] copy failed!" 1>&2 exit 1 fi We have added an if/fi block below the cp line. Bash Script Error Exit Using parameter expansion, it is possible to perform a number of useful string manipulations. there are dark corners in the Bourne shell, and people use all of them.

--Chet Ramey

The exit command terminates a script, Is there a way to achieve the same thing with a smaller impact? –blong Jul 29 '15 at 13:19 add a comment| up vote 10 down vote Inspired by the ideas

Bash Script Error Check

You can check for files with files open by using lsof. While Bash itself states the misspelled command being on line 34, the trap catches the error on line 45. Bash Script Error Command Not Found Let's consider this simple script: #!/bin/sh cp /Volumes/Documents/criticalfile.txt /Volumes/BackUp/. Bash Script Error Output echo "exit status of \"true\" = $?" # 0 !

So, thank you a lot! (I'm used to proram Java, and checking for a directory in an if statement is not exactly common in Java) –Thomas De Wilde Oct 22 '13 weblink Commands in subshell only lead to exiting the subshell, not the parent: set -e; (false); echo foo displays foo. 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. COMMAND_LAST # Will exit with status of last command. Bash Script Error Log

For the sake of this example, the directory MUST NOT exist, so the script effectively fails upon execution. One thing I have noticed is sometimes scripts use exit codes and sometimes they don't. So what can you do about it? navigate here Which requires more energy: walking 1 km or cycling 1 km at the same speed?

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 Bash Script Error Handling Trap 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 [ Improving the error exit function There are a number of improvements that we can make to the error_exit function.

This script design even permits you to track and trace errors on single-line commands, which you almost never believed to fail.

echo '--> cleanup' return $exit_code } echo '<-- outer' } inner() { set -e echo '--> inner' some_failed_command echo '<-- inner' } outer Here is the generic function that builds upon We can also use this variable within our script to test if the touch command was successful or not. On each "check" I also pass as a parameter the "message" of what the error is for logging purposes. #!/bin/bash error_exit() { if [ "$?" != "0" ]; then log.sh "$1" Error Integer Expression Expected Broken code get noticed because functioning code is the primary concern. –Draemon Jul 11 '14 at 18:54 @Draemon, the function keyword is bad practice, introducing gratuitous incompatibility with POSIX

Also, the sample trap handler presented herein can be extended to do virtually anything, from adding additional information like the environment, to submitting errors into a MySQL database, sending SNMP traps, That usage is simply a style thing. you should create a github project for it, so people can easily make improvements and contribute back. his comment is here Will the medium be able to last 100 years?

Line four gives us the "format" command not found, while line five is the message from the trap handler. environment variable contains the exit status of the previous program. Unexpected parent process id in output How rich can one single time travelling person actually become? Aborting." fi AND and OR lists Finally, we can further simplify our script by using the AND and OR control operators.

A possible solution to this is to use IO redirection and bash's noclobber mode, which won't redirect to an existing file.