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Bash Script Error Codes

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true\" = $?" # 1 # Note that the "!" needs a space between it and the command. # !true leads to a "command not found" error # # The '!' An exit value greater than 255 returns an exit code modulo 256. To understand the nature of the error these codes need to be interpreted. Although for this specific question, it is enough to set $? this contact form

Thanks, and fixed of course. –unwind May 4 '12 at 13:20 add a comment| up vote 2 down vote Some of answers rely on rewriting the code. 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 environment variable. $? You can check for files with files open by using lsof.

Bash Script Exit Code Of Last Command

Symbolic comparison of recursive functions Did Donald Trump call Alicia Machado "Miss Piggy" and "Miss Housekeeping"? I accepted a counter offer and regret it: can I go back and contact the previous company? Meaning of Guns and ghee Can filling up a 75 gallon water heater tank without opening a faucet cause damage? What you propose would also work, but isn't necessary. –Dennis Williamson Jul 14 '15 at 4:40 should totally accept this answer!!! –Tony Jul 7 at 9:08 add a comment|

Another example is rm. Unfortunately shell scripts are full of subtle effects which result in scripts failing in unusual ways. Why did companions have such high social standing? Bash Script Error Log Now I know my ABCs, won't you come and golf with me?

In our example this isn't a problem as apache opens the files every request. Bash Script Error Command Not Found Fortunately bash provides you with set -u, which will exit your script if you try to use an uninitialised variable. Is the standard Canon 18-55 lens the same as 5 years ago? david% touch "foo bar" david% find | xargs ls ls: ./foo: No such file or directory ls: bar: No such file or directory david% find -print0 | xargs -0 ls ./foo

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 $? Bash Script Error Message 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 This is Bash's way of giving functions a "return value." [1]

Following the execution of a pipe, a $? gives the exit status of with bash: The exit codes are provided in the PIPESTATUS special array.

Bash Script Error Command Not Found

You then need to use -0 with xargs. Program defensively - expect the unexpected Your script should take into account of the unexpected, like files missing or directories not being created. Bash Script Exit Code Of Last Command Since exit code 1 signifies so many possible errors, it is not particularly useful in debugging.

There has been an attempt to systematize exit status numbers (see /usr/include/sysexits.h

Join them; it only takes a minute: Sign up In bash, how to set a return code? http://sovidi.com/bash-script/bash-script-error-log.php For instance, see my crc32 script. command1 || exit; command2 || exit; The Bash will also store the exit code of the last command in the variable $?. Ending a script with exit 127 would certainly cause confusion when troubleshooting (is the error code a "command not found" or a user-defined one?). Bash Script Error Output

This should be changed to [ $rc -ne 0 ]. Another example to clarify further: spd-say "[email protected]" [ $? -ne 127 ] && exit $? cmd1 exit code is in ${PIPESTATUS[0]}, cmd3 exit code in ${PIPESTATUS[2]}, so that $? navigate here echo "Example of error with line number and message" error_exit "$LINENO: An error has occurred." The use of the curly braces within the error_exit function is an example of parameter expansion.

Unix & Linux Stack Exchange works best with JavaScript enabled Bash Script Error Handling Trap share|improve this answer edited Jan 7 at 1:24 answered Sep 18 '08 at 6:08 paxdiablo 488k1179691416 32 Same feature in just one line of portable code: ls -al file.ext || 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

An AND list has the form command1 && command2 command2 is executed if, and only if, command1 returns an exit status of zero.

no outgoing connection via ipv4 Are there any 'smart' ejection seats? It would be nice if you could fix these problems, either by deleting the lock files or by rolling back to a known good state when your script suffers a problem. 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 Shell Script Error Code 1 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

The above command will execute the ./tmp.sh script, and if the exit code is 0 the command echo "bam" will be executed. The last exit $? The answer is exit codes, exit codes are important and this article describes how to use them in your scripts and understand them in general. his comment is here The author of this document will not do fixups on the scripting examples to conform to the changing standard.

Aborting." 1>&2 exit 1 fi Here we check to see if the cd command is successful. Are there any 'smart' ejection seats? For example, when you create a directory, if the parent directory doesn't exist, mkdir will return an error. What to tell to a rejected candidate?

share|improve this answer edited Jun 13 '15 at 17:05 eadmaster 351414 answered Jun 13 '15 at 14:34 llua 3,582716 1 Valid for this particular example, but only usable if there When was this language released? In that case, the cd command will fail and the script executes the rm command on the current working directory. The Woz Monitor Finding a file starting with '-' dash Is 8:00 AM an unreasonable time to meet with my graduate students and post-doc?

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 share|improve this answer answered Jul 16 '15 at 16:55 don provan 212 add a comment| up vote 0 down vote You can use until to handle cases where #do something until