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I'll simplify it and hope I interpreted it right: cat <&1 1>file.log doesn't work. E.g. linux bash redirect stream pipe share|improve this question edited Dec 17 '15 at 16:27 Jahid 8,48542347 asked May 18 '09 at 4:19 flybywire 64.3k145334456 16 I would like to note http://onlinetvsoftware.net/bash-redirect/bash-redirect-error-to-out.php

I have learned a great deal about redirection. It is analogous to a file handle in C.

[3]Using file descriptor 5 might cause problems. Browse other questions tagged bash stdout stderr or ask your own question. What a helpful and badly needed site!

Bash Redirect To Dev Null

All rights reserved. filename="/home/ronnie/tmp/hello" date=$(date) echo "$date" >> $filename Now, lets suppose I change date=$(date) to date= $(date) which will generate an error. Now let's use exec to get another descriptor: exec 3I redirect stderr to stdout?

  • How to map and sum a list fast?
  • 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
  • Because after 2>&1, we have 2 file descriptors pointing to the same file.
  • If not, why?
  • Jan Schampera, 2015/10/21 06:51 It's a functionality of the shell itself, the shell duplicates the relevant file descriptors when it sees those filenames.
  • Based on this tutorial I implemented the following solution (I don't know how to produce an ampersand, therefore I use "amp;" instead): # save stdout, redirect stdout and stderr to a

For instance, if you open a file descriptor with exec 3>file, all the commands afterwards will inherit it. Then, execute ‘command' and redirect its STDOUT to ‘file-name'" - keeping in mind that at this point STDOUT will also contain whatever is written to STDERR because of the earlier redirection. It seems that /dev/stderr can have problem in cron. Linux Stdout Stderr This site is not affiliated with Linus Torvalds or The Open Group in any way.

First, a redirection into cat using a "here string". Linux Pipe Standard Error The syntax is (beside other redirection syntax) described here: http://bash-hackers.org/wiki/doku.php/syntax/redirection#appending_redirected_output_and_error_output share|improve this answer edited Mar 23 '14 at 11:24 Mathias Bynens 73.4k34147195 answered May 18 '09 at 4:42 TheBonsai 6,37731414 3 Let's see another use case. This syntax is deprecated and should not be used.

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 Bash Redirect Stderr And Stdout To Same File Unix & Linux Stack Exchange works best with JavaScript enabled ERROR The requested URL could not be retrieved The following error was encountered while trying to retrieve the URL: http://0.0.0.10/ Connection 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". Cool.

Linux Pipe Standard Error

I upvoted the accepted answer :) –Costi Ciudatu May 25 '14 at 19:10 2 &> now works as expected on OS X 10.11.1 (seems to be bash 3.2), just for Let's start with the outer { } 3>&2 4>&1. --- +-------------+ --- +-------------+ ( 0 ) ---->| /dev/pts/5 | ( 3 ) ---->| /dev/pts/5 | --- +-------------+ --- +-------------+ --- +-------------+ Bash Redirect To Dev Null Bash 4 introduced a warning message when end-of-file is seen before the tag is reached. Redirect Standard Error To File Convince people not to share their password with trusted others What are the canonical white spaces?

Why? check over here The shell's error stream is not redirected at this point. Can I log both the stderr and stdout logged to a file? 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 >& Linux Redirect Output To Stdout

It 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 What are the canonical white spaces? I'm very lost with this. his comment is here In practice, it could be a pipe, socket or whatever.

stdout goes to /dev/null, stderr still (or better: "again") goes to the terminal. Bash Redirect Stderr And Stdout To Different Files What does the "Phi" sign stand for in musical notation? script.sh 2>output.txt ā€¦stderr is not connected to terminal now, how can the scrip get know abot it??

Order of the redirections matters. –Jan Wikholm Jan 4 '15 at 12:51 1 does it mean, i should firstly redirect STDERROR to STDOUT, then redirect STDOUT to a file. 1

It's equivalent to > TARGET 2>&1 Since Bash4, there's &>>TARGET, which is equivalent to >> TARGET 2>&1. it cause original logfile is allways owerwritten. no outgoing connection via ipv4 How to handle spending money for extended trip to Europe? Bash Redirect Stderr To Variable Next Previous Contents Advanced Bash-Scripting Guide: PrevNext

Chapter 20.

Can Customs make me go back to return my electronic equipment or is it a scam? echo -n . >&3 # Write a decimal point there. asked 7 years ago viewed 344714 times active 7 months ago Get the weekly newsletter! weblink Hot Network Questions Natural construction What could cause the throttle to stick in my Ford Ranger?

You can also use 1 instead of 2 so that stdout gets redirected to the 'file' share|improve this answer answered Sep 24 '11 at 5:53 PaulDaviesC 512822 add a comment| Your It only happens on "preview", but it works for the real view. bash stdout stderr share|improve this question asked Oct 19 '12 at 12:25 ronnie 233238 add a comment| 2 Answers 2 active oldest votes up vote 6 down vote accepted The line exec 3>&1 4>&2 1> >(tee >(logger -i -t 'my_script_tag') >&3) 2> >(tee >(logger -i -t 'my_script_tag') >&4) trap 'cleanup' INT QUIT TERM EXIT get_pids_of_ppid() { local ppid="$1" RETVAL='' local pids=`ps x

An Example This example comes from this post (ffe4c2e382034ed9) on the comp.unix.shell group: { { cmd1 3>&- | cmd2 2>&3 3>&- } 2>&1 >&4 4>&- | cmd3 3>&- 4>&- } 3>&2 You will also notice that even in this scenario, terminal 1 does not see the PS3 prompt since it does not return a newline. asked 7 years ago viewed 331430 times active 4 months ago Linked 56 Piping both stdout and stderr in bash? 5 What's the correct way to redirect both stdout and stderr Thanks. –Mark Jul 14 '09 at 21:09 19 if you do cmd >>file1 2>>file2 it should achieve what you want. –Woodrow Douglass Sep 6 '13 at 21:24 | show 2

Generated Sun, 02 Oct 2016 00:18:16 GMT by s_hv987 (squid/3.5.20) Just something to keep in mind. 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 So it may depend on the shell (or shell compatibility level) you use in cron.

See also http://www.vincebuffalo.com/2013/08/08/the-mighty-named-pipe.html Real name: E-Mail: Website: Enter your comment. What does Sauron need with mithril? How do I redirect stderr to a file? In the same way, command 2> file will change the standard error and will make it point to file.

Wiki syntax is allowed: Please fill all the letters into the box to prove you're human. stdin, stdout, stderr When Bash starts, normally, 3 file descriptors are opened, 0, 1 and 2 also known as standard input (stdin), standard output (stdout) and standard error (stderr). keyboard) stdout1standard output stream (e.g. In it, you'll get: The week's top questions and answers Important community announcements Questions that need answers see an example newsletter By subscribing, you agree to the privacy policy and terms

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