Redirecting output N > TARGET This redirects the file descriptor number N to the target TARGET. Additionally it will not append to the file but it will overwrite it. –pabouk May 31 '14 at 12:38 Correct: File descriptor could be any values which is more The accepted answer do_something &>filename doesn't. +1. –Withheld Jan 4 '13 at 16:01 4 @Daniel, but this question is specifically about bash –John La Rooy Aug 19 '13 at 3:38 The classic and portable (Bash pre-4) way is: cmd >> outfile 2>&1 A nonportable way, starting with Bash 4 is cmd &>> outfile (analog to &> outfile) For good coding style, have a peek at this web-site
add a comment| 10 Answers 10 active oldest votes up vote 725 down vote accepted That part is written to stderr, use 2> to redirect it. How to explain the use of high-tech bows instead of guns Can I use GitHub and be PCI DSS compliant? Tagged with: error message, I/O redirection, keyboard, Linux, log program, program error, redirect stderr stdout to file, redirect stderr to file, redirect stdout to file, redirection, standard error, stderr, stdin, stdout, Accepted answer resolved this the right way. –AoeAoe Sep 6 '12 at 15:39 1 @AoeAoe: This actually works in Bash 4 too. –mk12 Sep 6 '12 at 21:11 1
Thanks Josef, 2012/03/23 01:26 How can I identify, which stream is connected to terminal and which is connected to somewhere else? The word after the <<< is expanded (variables, command substitutions, ...), but not pathname-expanded (*.txt, foo??.exe, ...), so: # this gives the contents of PATH variable cat <<< "$PATH" # this Thanks Jan Schampera, 2012/03/23 16:56 Using the test command on the file descriptors in question. [ -t 0 ] # STDIN [ -t 1 ] # STDOUT ... Using exec20.2.
Redirecting Code Blocks20.3. All rights reserved. If the option noclobber is set with the set builtin, with cause the redirection to fail, when TARGET names a regular file that already exists. Bash Echo To Stderr Which shell? –RhinoDevel May 20 at 14:15 1 this will work in both unix and linux and irrespective of shell we used. –UmayKnowMe May 23 at 16:31 add a comment|
Avoid referencing file descriptors above 9, since you may collide with file descriptors Bash uses internally. If you write a script that outputs error messages, please make sure you follow this convention! for real loggin better way is: exec 1>>$LOG_FILE it cause log is allways appended. –Znik Dec 8 '14 at 9:43 2 That's true although it depends on intentions. The position on the commandline does not really matter, a redirection (here document) is a redirection: # cat the two files plus "hello world" from standard input by here document redirection
These will be used as real terminal STDOUT and STDERR. 1> >(...) redirects STDOUT to command in parens parens(sub-shell) executes 'tee' reading from exec's STDOUT(pipe) and redirects to 'logger' command via Tee Stderr You da man! –Ogre Psalm33 Aug 4 '10 at 12:54 7 On AIX (ksh) your solution works. command >/dev/null 2>&1 See also Internal: Illustrated Redirection Tutorial Internal: The noclobber option Internal: The exec builtin command Internal: Simple commands parsing and execution Internal: Process substitution syntax Internal: Obsolete and share|improve this answer edited Sep 4 '15 at 15:14 answered Apr 9 '14 at 4:48 SJain 2,49931946 add a comment| up vote 17 down vote Use this - "require command here"
The > operator redirects the output usually to a file but it can be to a device. Reply Link Security: Are you a robot or human? Bash Redirect Stderr To Dev Null Browse other questions tagged linux bash io-redirection or ask your own question. Ambiguous Output Redirect If you don't specify a number then the standard output stream is assumed but you can also redirect errors > file redirects stdout to file 1> file redirects stdout to file
Success! Check This Out Usage:
share|improve this answer edited Oct 7 '10 at 5:44 David Johnstone 14.1k115568 answered Mar 12 '09 at 9:17 dirkgently 74.5k1294163 6 Somebody should restore to the second edit of this Cancel reply Leave a Comment Name Email Comment You can use these HTML tags and attributes:
Receive Email Notifications? Any idea why? –Alexandre Holden Daly May 30 '14 at 12:12 1 Note that (by default) this has the side-effect that $? Source First is: the redirection happens from left to right.
Relatively easy: initially, stdout points to your terminal (you read it) same applies to stderr, it's connected to your terminal 2>&1 redirects stderr away from the terminal to the target for Redirect Stdout And Stderr To File Windows Browse other questions tagged linux bash redirect stream pipe or ask your own question. How do we know Neanderthals DNA?
They're evaluated from left to right. Can I log both the stderr and stdout logged to a file? exec 3<> File # Open "File" and assign fd 3 to it. Redirect Stdout To File C Bash / ksh and other modern shell on Linux has three file descriptors: stdin (0) stdout (1) stderr (2) Syntax To redirect all output to file The syntax is as follows
The redirection operators are checked whenever a simple command is about to be executed. What is way to eat rice with hands in front of westerners such that it doesn't appear to be yucky? In practice, it could be a pipe, socket or whatever. have a peek here as you can see.
It is analogous to a file handle in C.Using file descriptor 5 might cause problems. For opening additional files, there remain descriptors 3 to 9. Let's assume we have terminal connected to /dev/stdout(FD #1) and /dev/stderr(FD #2). A slightly more correct is: The output of the ‘command' is redirected to a ‘file-name' and the error chanel (that is the ‘2' is redirected to a pointer (?) of the