When you run a script that gives you an output and if we add a > /dev/null 2>&1 at the end of the script, we are asking the script to write add a comment| 6 Answers 6 active oldest votes up vote 62 down vote accepted > is for redirect /dev/null is a black hole where any data sent, will be discarded If those answers do not fully address your question, please ask a new question. Browse other questions tagged bash shell redirect pipe or ask your own question. have a peek at this web-site
Changing to >&3 may help. –quizac Sep 23 '14 at 17:40 add a comment| up vote 1 down vote For tcsh, I have to use the following command : command >& Thank you Giuseppe for the tip. up vote 54 down vote favorite 34 I want one or two line description about the following command line: grep -i 'abc' content 2>/dev/null command-line grep stdout share|improve this question edited file iplist has a long list of IP's on the network and i need to send this to a script that creates a file with the ping info.
Reference I/O Redirection share|improve this answer answered Oct 21 '14 at 13:13 geedoubleya 2,103718 add a comment| up vote 2 down vote Normally when cron executes a cronjob it sends the Code Golf Golf Golf How to search for flights for a route staying within in an alliance? It almost work, but not from xinted ;( share|improve this answer answered Apr 23 '09 at 13:14 log-control I'm guessing it doesn't work because of "/dev/fd/3 Permission denied". Reply Link Frank June 30, 2009, 5:15 pm need a command in my bash script to remove some (not all) of the contents of directory2.
Also see http://bash-hackers.org/wiki/doku.php/howto/redirection_tutorial share|improve this answer edited Aug 25 '12 at 0:26 answered Aug 19 '12 at 14:22 geirha 2,6081021 add a comment| up vote 4 down vote How about this: The other is to append. Didn't know that one. Redirect Only Stdout To Dev Null briefly: all STDERR and STDOUT messages will be redirect to /dev/null share|improve this answer edited Oct 21 '14 at 13:14 slm♦ 167k40305474 answered Oct 21 '14 at 13:11 arash javan 25819
But, if you can't figure it out on your own, you shouldn't try, as you are more likely to break something fatally than succeed. –Benubird May 13 '13 at 8:11 Redirect Stdout To Dev Null How come Ferengi starships work? Computing only one byte of a cryptographically secure hash function しっているはずです is over complicated? http://unix.stackexchange.com/questions/163352/what-does-dev-null-21-mean-in-this-article-of-crontab-basics To break it up: 2 is the handle for standard error or STDERR 1 is the handle for standard output or STDOUT 2>&1 is asking to direct all the STDERR as
Bitwise rotate right of 4-bit value Do I need to turn off camera before switching auto-focus on/off? Redirect Stderr To Dev Null And Stdout To File Forgotten Lost Highway (New Zealand ) - Is it advisable to do it in a rental car? share|improve this answer answered Oct 21 '14 at 13:13 garethTheRed 16.2k23148 1 What if the command that I run in the crontab file do not output anything? 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
Draw an hourglass Alphabet Diamond "Guard the sense doors"- What does this mean, and what is it's application? http://askubuntu.com/questions/350208/what-does-2-dev-null-mean So, you discard the output and cron has nothing to send. Redirect Error To Dev Null This site is not affiliated with Linus Torvalds or The Open Group in any way. & Dev Null There are always three default files open.
This functionality is provided by 'tee' command which can write/append to several file descriptors(files, sockets, pipes, etc) at once: tee FILE1 FILE2 ... >(cmd1) >(cmd2) ... Check This Out Alphabet Diamond Does the Iron Man movie ever establish a convincing motive for the main villain? If so, why is it allowed? That I found I even can't find a flexible way to do this in one-line command with sh. 1 Dev Null
My approach is to always create a unique and timestamped log file. Redirect Output To Null Windows share|improve this answer answered Aug 19 '12 at 14:22 Charlie Martin 77.4k15137218 2 You're a good guy, Charlie, so +1. Reply Link Martin June 2, 2014, 4:23 am You could use find instead to filter out the files you don't want to delete, or only delete files matching a patter: Delete
I know it's not recommended, but for someone like myself, with scripts they either run daily or don't run for months and then go through a spate of executing them two File descriptor 2 is still redirected to stdout, no matter what happens to file descriptor 1. Cannot patch Sitecore initialize pipeline (Sitecore 8.1 Update 3) What are the difficulties of landing on an upslope runway What are the differences between update and zip packages What to do What Is /dev/null In Linux How to explain the concept of test automation to a team that only knows manual testing?
to treat all the error messages generated from the script as its standard output). How does the exit command work on a Unix terminal? briefly: all STDERR and STDOUT messages will be redirect to /dev/null share|improve this answer edited Oct 21 '14 at 13:14 slm♦ 167k40305474 answered Oct 21 '14 at 13:11 arash javan 25819 have a peek here in the first example you wrote: exec 1<>$LOG_FILE .
Modo di dire per esprimere "parlare senza tabù" Does dropping a Coursera course look bad in a PhD application to the university offering the course? Nobody I asked could tell me what the funny greater-thans, ampersands and numbers after the commands meant, and search engines never turned up anything but examples of it being used without Jul 13 at 13:30 This question has been asked before and already has an answer. Conventionally, file descriptor '1' is standard output (a.k.a.
Cannot patch Sitecore initialize pipeline (Sitecore 8.1 Update 3) Does WiFi traffic from one client to another travel via the access point? To the author of the original post, It depends what you need to achieve. 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 RSS Feed.
Related 369Redirect stderr and stdout in a Bash script743How can I redirect and append both stdout and stderr to a file with Bash?552How to pipe stderr, and not stdout?1bash output redirect A mail is delivered only when there is output on stdout or stderr. Reply Link Jonathan May 26, 2009, 9:31 pm Thanks! How to explain the concept of test automation to a team that only knows manual testing?
I'm sure you have something in mind where both good and bad output would normally go to stdout. Save a JPG without a background Some part of my plot has been hiding If you're given an hour, is it bad to finish a job talk in half an hour? Much more information is available at The Linux Documentation Project's I/O Redirection page.