Direct Standard Error To Standard Output
Contents |
>20.3. Applications
Redirect Standard Error And Output To File Windows
is sometimes useful to assign one of these additional file descriptors to stdin, stdout, or stderr as a temporary duplicate link. [3] This simplifies restoration to normal after complex redirection and reshuffling (see Example 20-1).
COMMAND_OUTPUT > # Redirect stdout to a file. # Creates the file if not present, otherwise overwrites it. ls -lR > dir-tree.list # Creates a file containing a listing of the directory standard output and standard error in unix tree. : > filename # The > truncates file "filename" to zero length. # If file not present, creates zero-length file (same effect as 'touch'). # The : serves as a dummy placeholder, producing no output. > filename # The > truncates file "filename" to zero length. # If file not present, creates zero-length file (same effect as 'touch'). # (Same result as ": >", above, but this does not work with some shells.) COMMAND_OUTPUT >> # Redirect stdout to a file. # Creates the file if not present, otherwise appends to it. # Single-line redirection commands (affect only the line they are on): # -------------------------------------------------------------------- 1>filename # Redirect stdout to file "filename." 1>>filename # Redirect and append stdout to file "filename." 2>filename # Redirect stderr to file "filename." 2>>filename # Redirect and append stderr to file "filename." &>filename # Redirect both stdout and stderr to file "filename." # This operator is now functional, as of Bash 4, final release. M>N # "M" is a file descriptor, which defaults to 1, if not explicitly set. # "N" is a filename. # File descriptor "M" is redirect to file "N." M>&N # "M" is a file descriptor, which defaults to 1, if not set. # "N" is another file descriptor. #============================================================================== # Redirecting stdout, one line at a time. LOGFILE=script.log echo "This statement is sent to the log file,12, 2008 in BASH Shell, Linux, UNIXQ. How do I redirect stderr to stdout? How do I linux pipe standard error redirect stderr to a file? A. Bash and other modern shell
Redirect Stderr To Dev Null
provides I/O redirection facility. There are 3 default standard files (standard streams) open: [a] stdin -
Bash Redirect Stderr To Dev Null
Use to get input (keyboard) i.e. data going into a program.
[b] stdout - Use to write information (screen)[c] stderr - Use to write error message (screen)Understanding http://www.tldp.org/LDP/abs/html/io-redirection.html I/O streams numbersThe Unix / Linux standard I/O streams with numbers:HandleNameDescription0 stdin Standard input1 stdout Standard output2 stderr Standard errorRedirecting the standard error stream to a fileThe following will redirect program error message to a file called error.log: $ program-name 2> error.log$ command1 2> error.logRedirecting the standard error (stderr) and stdout http://www.cyberciti.biz/faq/redirecting-stderr-to-stdout/ to fileUse the following syntax: $ command-name &>file OR $ command > file-name 2>&1 Another useful example: # find /usr/home -name .profile 2>&1 | moreRedirect stderr to stdoutUse the command as follows: $ command-name 2>&1 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:How do I save or redirect stdout and stderr into different files?Linux Redirect Error Output To FileBASH Shell Redirect Output and Errors To /dev/nullUnix and Linux: Redirect Error Output To null CommandPrinting output of c program to a file in LinuxUnix / Linux: Save Output To FilePython Run External Command And Get Output On Screen or In VariablePython Execute Unix / Linux Command ExamplesLinux / Unix Find Command: Avoid Permission Denied MessagesHow to gzip and keep original file on Unix or Linux command line{ 11 comments…
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 answers to any questions you might have Meta http://askubuntu.com/questions/625224/how-to-redirect-stderr-to-a-file Discuss the workings and policies of this site About Us Learn more http://unix.stackexchange.com/questions/80629/redirect-both-stderr-and-stdout-to-dev-null-with-bin-sh about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Ask Ubuntu Questions Tags Users Badges Unanswered Ask Question _ Ask Ubuntu is a question and answer site for Ubuntu users and developers. Join them; it only takes a minute: Sign up standard error Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top How to redirect stderr to a file up vote 7 down vote favorite 1 While using nohup to put a command to run in background some of content appear in terminal. cp: error reading ‘/mnt/tt/file.txt’: Input/output direct standard error error cp: failed to extend ‘/mnt/tt/file.txt’: Input/output error I want to save that content to a file. command-line redirect share|improve this question edited May 18 '15 at 13:42 asked May 18 '15 at 12:31 André M. Faria 3861618 add a comment| 1 Answer 1 active oldest votes up vote 12 down vote accepted There are two main output streams in Linux (and other OSs), standard output (stdout)and standard error (stderr). Error messages, like the ones you show, are printed to standard error. The classic redirection operator (command > file) only redirects standard output, so standard error is still shown on the terminal. To redirect stderr as well, you have a few choices: Redirect stderr to another file: command > out 2>error Redirect stderr to stdout (&1), and then redirect stdout to a file: command >out 2>&1 Redirect both to a file: command &> out For more information on the various control and redirection operators, see here. share|improve this answer answered May 18 '15 at 12:50 terdon♦ 41.9k686152 So 'hashdeep -rXvvl -j 30 -k checksums.txt /mnt/a
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 site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers or posting ads with us Unix & Linux Questions Tags Users Badges Unanswered Ask Question _ Unix & 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 can ask a question Anybody can answer The best answers are voted up and rise to the top Redirect both stderr and stdout to /dev/null with /bin/sh up vote 20 down vote favorite 5 Tried all sorts of ways to redirect both stdout and stderr to /dev/null without any success. I have almost my entire life run bash which i've never had this issue with but for once in BSD i'm stuck with /bin/sh. What i've tried: if ls ./python* 2> /dev/null; then echo found Python fi Which works, if Python is not present it will mute the error messages from ls. However, if python.tgz is present a line with be outputted which looks like this: # ./test.sh ./python-2.7.3p1.tgz And i've tried: if ls ./python* &> /dev/null; then echo found Python fi and if ls ./python* 2>1 > /dev/null; then echo found Python fi and if ls ./python* > /dev/null; then echo found Python fi Nothing really works. I can only redirect one of the outputs, not both at the same time. shell io-redirection openbsd share|improve this question asked Jun 25 '13 at 19:12 Torxed 72531028 add a comment| 1 Answer 1 active oldest votes up vote 37 down vote accepted I believe what you are looking for is: ls good bad >/dev/null 2>&1 You have to redirect stdout first before duplicating it into stderr; if you duplicate it first, stderr will just point to what stdout originally pointed at. In bash you can do this with &>/dev/null but that's a bash extension. share|improve this answer edited Jun 26 '13 at 7:49 l0b0 17.3k1067142 answered Jun 25 '13 at 19:22 rici 6,0681625 1 Indeed, i read the bourn shell manual. It stated that later versions of /bi