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Bash Redirecting Standard Error


shell io-redirection file-descriptors csh portability share|improve this question edited May 21 '14 at 8:40 Gilles 369k666681119 asked Apr 3 '13 at 1:25 Det 478156 1 Note that, while mksh supports Best leave this particular fd alone.

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current community They're just syntactic sugar, just use > file 2>&1 which is standard and portable (to Bourne-like shells). –Stéphane Chazelas Dec 9 '14 at 14:26 | show 2 more comments Your Answer My experience with those 2 compared to bash's redirection operators, is that bash is superior in that regard. http://sovidi.com/bash-redirect/bash-redirecting-standard-error-to-standard-output.php

bash chose &> (now also supported by zsh and some pdksh derivatives) though it clearly breaks POSIX compliance since foo &> file is perfectly valid POSIX syntax which means something completely How would family relationships change if legal system uses collective punishment? Wiki syntax is allowed: Please fill all the letters into the box to prove you're human. share|improve this answer edited Oct 25 '14 at 20:36 Jonathan Callen 31018 answered Apr 3 '13 at 3:44 slm♦ 164k40298469 We have a winner.

Bash Redirect Standard Error To /dev/null

UNIX is a registered trademark of The Open Group. This will close output for whichever file descriptor is referenced, i.e. "M". 2>/dev/null The general form of this one is M>/dev/null, where "M" is a file descriptor number. To be precise, the following substitutions and expansions are performed in the here-document data: Parameter expansion Command substitution Arithmetic expansion You can avoid that by quoting the tag: cat <<"EOF" This Related 2Difference between > and | with /dev/tty6the usage of < /dev/null & in the command line4“>/dev/null 2>&1” in `if` statement7Is this redirecting to /dev/null?53Is >&- more efficient than >/dev/null?3Meaning of

  1. It's a mighty tool that, together with pipelines, makes the shell powerful.
  2. your complete shell script with multiple echo statements } > 2>&1 | tee -a script.log Reply Link aref ghobadi August 15, 2015, 9:56 amHi thanks a lot Reply Link karthikeyan December
  3. The system returned: (22) Invalid argument The remote host or network may be down.
  4. Avoid referencing file descriptors above 9, since you may collide with file descriptors Bash uses internally.
  5. The order is important!
  6. Redirection simply means capturing output from a file, command, program, script, or even code block within a script (see Example 3-1 and Example 3-2) and sending it as input
  7. asked 3 years ago viewed 24425 times active 3 years ago Linked 0 Some errors are not logged, after redirecting both stderr and stdout to a file Related 17Show only stderr
  8. cat File # ==> 1234.67890 # Random access, by golly. | # Pipe. # General purpose process and command chaining tool. # Similar to ">", but more general in effect.
  9. The TARGET is not truncated before writing starts.

TAG A here-document is an input redirection using source data specified directly at the command line (or in the script), no "external" source. Thanks Jan Schampera, 2012/03/23 16:56 Using the test command on the file descriptors in question. [ -t 0 ] # STDIN [ -t 1 ] # STDOUT ... bad_command2 2>>$ERRORFILE # Error message appended to $ERRORFILE. Bash Redirect Stderr Pipe Consider it a simplified type of file pointer.

If you have to use operands (e.g. up vote 24 down vote favorite 12 This does not make sense to me. Next Previous Contents Advanced Bash-Scripting Guide: PrevNextChapter 20. share|improve this answer edited Jun 26 '13 at 7:49 l0b0 17.2k1067141 answered Jun 25 '13 at 19:22 rici 6,0681625 1 Indeed, i read the bourn shell manual.

What does an 'ü' mean? Bash Redirect Stdin If you want to redirect both, stderr and stdout to the same file (like /dev/null, to hide it), this is the wrong way: # { echo OUTPUT; echo ERRORS >&2; } See also rc for better designed operators. –Stéphane Chazelas Oct 24 '14 at 9:26 Update: about the performance issue, that's also confirmed here: unix.stackexchange.com/questions/163955/… –Det Apr 16 at 14:24 ERRORFILE=script.errors bad_command1 2>$ERRORFILE # Error message sent to $ERRORFILE.

Bash Redirecting Stderr And Stdout To Same File

more hot questions question feed lang-sh about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation EOF These are 2 things: a redirection (here-document EOF) a pathname expansion which MAY generate commandline arguments to cat These things are independent. Bash Redirect Standard Error To /dev/null I'm very lost with this. Bash Redirect Stderr And Stdout To Different Files Were slings used for throwing hand grenades?

ls -l 2>&1 >&3 3>&- | grep bad 3>&- # Close fd 3 for 'grep' (but not 'ls'). # ^^^^ ^^^^ exec 3>&- # Now close it for the remainder of http://sovidi.com/bash-redirect/bash-redirecting-error-messages.php Portability to non-bash, tcsh, mksh, etc. Please keep this field empty: Show pagesource Old revisions Backlinks syntax/redirection.txt ยท Last modified: 2013/04/14 14:30 by thebonsai This site is supported by Performing Databases - your experts for database STDOUT) a number 2 = standard error (i.e. Bash Redirect Stderr To Variable

Can filling up a 75 gallon water heater tank without opening a faucet cause damage? why? Are there any 'smart' ejection seats? http://sovidi.com/bash-redirect/bash-redirecting-standard-output-and-standard-error.php Here strings <<< WORD The here-strings are a variation of the here-documents.

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. Bash Redirect Stderr And Stdout To File And Screen Can I use an HSA as investment vehicle by overcontributing temporarily? Jan Schampera, 2011/02/14 06:31 These are 2 cases.

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

Follow him on Twitter. See the page about obsolete and deprecated syntax. For example, the command ls > dirlist 2>&1 directs both standard output and standard error to the file dirlist, while the command ls 2>&1 > dirlist directs only the standard output Bash Redirect Stderr Append How to indicate you are going straight?

This will lead to both stderr and stdout go to file-name. I still think logically its confusing. This site is not affiliated with Linus Torvalds or The Open Group in any way. navigate here Generated Sun, 02 Oct 2016 00:30:20 GMT by s_hv1000 (squid/3.5.20)

John, 2015/10/28 21:59 Probably worth highlighting the link with Process Substitution in a more prominent way than the "See Also: process substitution syntax" link, since it's a close relative and possibly UNIX is a registered trademark of The Open Group. If N is omitted, filedescriptor 0 (stdin) is assumed. asked 3 years ago viewed 73118 times active 1 year ago Linked 0 What does this ls command do? 53 Is >&- more efficient than >/dev/null? 0 Cron job not logging?

How to pluralize "State of the Union" without an additional noun? Browse other questions tagged shell io-redirection file-descriptors csh portability or ask your own question.