How To Capture Error Message In Unix
Contents |
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this bash error message variable site About Us Learn more about Stack Overflow the company Business Learn more about
How To Capture Error Message In Shell Script
hiring developers or posting ads with us Unix & Linux Questions Tags Users Badges Unanswered Ask Question _ Unix &
Shell Script Error Handling
Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute: Sign up Here's how it works: Anybody
Bash Capture Error Message
can ask a question Anybody can answer The best answers are voted up and rise to the top How to capture error message from executed command? up vote 5 down vote favorite 1 I was tasked to create an automated server hardening script and one thing that they need is a report of all the output of each command executed. I want to store the error bash get error message message inside a string and append it in a text file. Let's say I ran this command: /sbin/modprobe -n -v hfsplus The output of running this in my machine would be: FATAL: Module hfsplus not found How can I store that error message inside a string? Any help would be greatly appreciated. Thanks! bash scripting string share|improve this question asked May 29 '14 at 7:25 Miguel Roque 1173412 I tried running this command: var=$(/sbin/modprobe -n -v hfsplush) And then displaying it: $var But it still doesn't capture the error message inside the string. –Miguel Roque May 29 '14 at 7:42 add a comment| 4 Answers 4 active oldest votes up vote 10 down vote you can do it by redirecting errors command: /sbin/modprobe -n -v hfsplus 2> fileName as a script #!/bin/bash errormessage=$( /sbin/modprobe -n -v hfsplus 2> &1) echo $errormessage or #!/bin/bash errormessage=`/sbin/modprobe -n -v hfsplus 2> &1 ` echo $errormessage if you want to append the error use >> instead of > share|improve this answer edited May 29 '14 at 7:48 answered May 29 '14 at 7:42 Networker 4,72962856 I've tried that approach and it stores it DIRECTLY in the text file.
Scripting Unix shell scripting - KSH, CSH, SH, BASH, PERL, PHP, SED, AWK and shell scripts and shell scripting languages here. Search Forums Show Threads Show Posts Tag Search Advanced Search Unanswered Threads Find bash print error message All Thanked Posts Go to Page... unix and linux operating commands How to capture bash catch error actual error message when a command fails to execute Shell Programming and Scripting Thread Tools shell script exit code Search this Thread Display Modes #1 04-26-2009 prathima Registered User Join Date: Apr 2008 Last Activity: 26 April 2009, 12:49 PM EDT Posts: 5 Thanks: 0 Thanked 0 Times in 0 Posts http://unix.stackexchange.com/questions/132511/how-to-capture-error-message-from-executed-command How to capture actual error message when a command fails to execute I want to capture actual error message in case the commands I use in my shell script fails. For eg: ls -l abc.txt 2>>errorlog.txt In this case I understand the error message is written to the errorlog.txt and I assume its bacause the return code from the command ls -l abc might return 2 if "abc" doesnt exists. My question is: http://www.unix.com/shell-programming-and-scripting/108220-how-capture-actual-error-message-when-command-fails-execute.html How about if the command return non zero return code and is not equal to 2? I want to do something like this: ls -l abc.txt if [$? -ne 0] then echo $errorMessage >> errorlog.txt fi where I want actual error message that the command has returned to be written to errorlog.txt. Just for understanding I used $errorMessage but I assume there should be some means to capture the actual error message which can later be stored in errorMessage or written directly to errorlog.txt. Can someone please help? Remove advertisements Sponsored Links prathima View Public Profile Find all posts by prathima #2 04-26-2009 devtakh Unix Enthusiatic Join Date: Oct 2007 Last Activity: 21 August 2013, 5:20 AM EDT Location: Bangalore Posts: 738 Thanks: 0 Thanked 7 Times in 7 Posts Quote: Originally Posted by prathima I want to capture actual error message in case the commands I use in my shell script fails. For eg: ls -l abc.txt 2>>errorlog.txt In this case I understand the error message is written to the errorlog.txt and I assume its bacause the return code from the command ls -l abc might return 2 if "abc" doesnt exists. Quote: Here, 2 is not the return code. 2 is the File descriptor value(FD). By default, the st
do I redirect error messages? Note: The following information pertains primarily to Bourne-like shells, such as sh, ksh, and bash. To redirect standard error messages to a file, enter: command 2> file Replace command https://kb.iu.edu/d/agvw with the command you want to execute and file with the file to which http://www.cyberciti.biz/faq/linux-redirect-error-output-to-file/ you want to direct the errors, for example: gunzip * 2> ~/errors If you wish to suppress error messages, enter: command 2>&- If you wish to redirect error messages to standard output, enter: command 2>&1 You can direct both standard error and standard out messages to an output file by entering the following: command > file error message 2>&1 The csh and tcsh shells have substantially less flexible redirection capabilities. However, from sh or tcsh you can invoke a Bourne-like shell to run a command that redirects standard error messages. To redirect standard error messages, enter the following: ksh -c 'commands' You can use sh or bash in the place of ksh. Replace commands with redirection syntax, for example: ksh -c 'ls -l foo 2> ~/notfound' At Indiana University, capture error message for personal or departmental Linux or Unix systems support, see At IU, how do I get support for Linux or Unix? Related documents Introduction to Unix commands In Unix, where can I get information on differences between the various shells? This is document agvw in the Knowledge Base. Last modified on 2008-08-22 00:00:00. I need help with a computing problem Fill out this form to submit your issue to the UITS Support Center. Please note that you must be affiliated with Indiana University to receive support. All fields are required. Full name Email address Please provide your IU email address. If you currently have a problem receiving email at your IU account, enter an alternate email address. Relationship to Indiana University --Select One-- Student Faculty member Staff member Affiliate Alumnus/Alumna Applicant Emeritus faculty member Parent Retired staff member Other Please enter your question or describe your problem Captcha Submit I have a comment for the Knowledge Base Fill out this form to submit your comment to the IU Knowledge Base. If you are affiliated with Indiana University and need help with a computing problem, please use the I need help with a computing problem section above, or contact your campus Support Center. Full name Email address Please provide your I
am a new Ubuntu Linux and bash shell user. I also know how to redirect output from display/screen to a file using the following syntax:
cmd > file ls > fileHowever, some time errors are displayed on screen. How do I store and redirect output from the computer screen to a file on a Linux or Unix-like systems? Bash / ksh and other modern shell on Linux has three file descriptors:stdin (0)stdout (1)stderr (2)Syntax To redirect all output to fileThe syntax is as follows to redirect output (stdout) as follows:command-name > output.txt command-name > stdout.txtSyntax To redirect all error to fileThe syntax is as follows to redirect errors (stderr) as follows:command-name 2> errors.txt command-name 2> stderr.txtSyntax to redirect both output (stdout) and errors (stderr) to different filesThe syntax:command1 > out.txt 2> err.txt command2 -f -z -y > out.txt 2> err.txtSyntax to redirect both output (stdout) and errors (stderr) to same fileThe syntax is:command1 > everything.txt 2>&1 command1 -arg > everything.txt 2>&1Syntax to redirect errors (stderr) to null or zero devicesData written to a null or zero special file is discarded by your system. This is useful to silence out errors (also know as ‘error spam'):command1 2> /dev/null command1 2> /dev/zero command2 -arg 2> /dev/null command2 -arg 2> /dev/zeroTip: Use tee command to redirect to both a file and the screen same timeThe syntax is:command1 |& tee log.txt ## or ## command1 -arg |& tee log.txt ## or ## command1 2>&1 | tee log.txtAnother usage:#!/bin/bash # My script to do blah ... foo(){ : } 2>&1 | tee foo.logOR#!/bin/bash # My script to do blah ... { command1 command2 } 2>&1 | tee script.log Share this tutorial on:TwitterFacebookGoogle+Download PDF version Found an error/typo on this page?About the author: Vivek Gite is a seasoned sysadmin and a trainer for the Linux/Unix & shell scripting. Follow him on Twitter. OR read more like this:BASH Shell Redirect Output and Errors To /dev/nullBASH Shell: How To Redirect stderr To stdout ( redirect stderr to a File )Unix and Linux: Redirect Error Output To null CommandHow do I save or redirect stdout and stderr into different files?Linux / Unix Find Command: Avoid Permission Denied