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Bash Script Redirect Error To Variable


Redirecting Code Blocks >20.3. IT, Linux bash, stderr, stdout Comments are closed. I know it's performance-safe because my parent code calls this less than 100 times during the entire program, and the user will never notice 100 getopt calls vs 200 getopt calls. Let's say you want only the stderr, but not stdout. this contact form

grep foo somelogfile | head -5; then 3 printf "uh oh\n" 4 fi Now, some trickier stuff. This approach will also likely be prone to race conditions. –James Haigh Apr 29 '15 at 8:53 add a comment| up vote 0 down vote Here's a simpler variation that isn't Is it possible to check for existence of member template just by identifier? The redirection applies only to the program itself.

Bash Backticks Stderr

error=$1 shift # Local AWK program to extract the error, the result, and the exit code # parts of the captured output of command. How to deal with a really persuasive character? But at least the ugly stuff is wrapped in a function.

So it will be easier to analyse the following sequence: $(...3>&22>&11>&33>&-) Redirection fd 0 (stdin) fd 1 (stdout) fd 2 (stderr) fd 3 Description initial /dev/tty /dev/tty /dev/tty Let's assume this Unix & Linux Stack Exchange works best with JavaScript enabled current community chat Unix & Linux Unix & Linux Meta your communities Sign up or log in to customize your list. Religious supervisor wants to thank god in the acknowledgements Is 8:00 AM an unreasonable time to meet with my graduate students and post-doc? Bash Script Redirect Stderr To Dev Null I haven't quite gotten it to work yet.

I've mainly used this for code that runs during the boot sequence when you don't yet know if the disk is going to be working. Bash Script Redirect Output To Variable But I need some output even in non-verbose mode, therefore I can't just redirect whole stdout and stderr, only from some commands inside of my script. Join them; it only takes a minute: Sign up How to store standard error in a variable in a Bash script up vote 88 down vote favorite 35 Let's say I You mentioned the return code of the command too.

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 Bash Redirect Append If you want to capture the output, you use command substitution: 1 output=$(command) # stdout only; stderr remains uncaptured 2 output=$(command 2>&1) # both stdout and stderr will be captured 3 Change banana to: banana() { echo "banana to stdout" echo >&2 "banana to stderr" return 42 } We'll also have the return code of banana in the variable bret like so: Not sure why, but > >() seems to work reliably.

Bash Script Redirect Output To Variable

share|improve this answer edited Jun 16 '15 at 21:21 Neil 10k73448 answered Dec 10 '12 at 18:12 zb' 5,79612053 Thanks - accepting this answer because using file descriptors 3 The close isn't really needed if the script exits immediately afterwards. –Jonathan Leffler Jun 11 '09 at 22:01 How would I capture both stderr and stdout in variables? –Gingi Bash Backticks Stderr The trouble here is that a is evaluated and assigned in a sub-shell, and the assignment in the sub-shell does not affect the parent shell. (Tested on Ubuntu 14.04 LTS as Bash Script Redirect Output To File And Screen ERROR=$(command 3>&1 1>&2 2>&3 | tee /dev/stderr) ERROR=$(command 3>&1 1>&2 2>&3 | tee /proc/self/fd/2) ERROR=$(command 3>&1 1>&2 2>&3 | tee >(cat - >&2)) Good reading: Bash FAQ: How can I store

asked 7 years ago viewed 102312 times active 10 months ago Visit Chat Linked 28 Bash script - store stderr in variable 0 Store the output of command in variable in http://gatoisland.com/bash-script/bash-script-set-error.php Least Common Multiple How to increase the population growth of the human race Is my workplace warning for texting my boss's private phone at night justified? You can mimic such a command with a function: banana() { echo "banana to stdout" echo >&2 "banana to stderr" } I'll assume you want standard output of banana in variable 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 Bash Script Redirect Output To Null

What does the "Phi" sign stand for in musical notation? See my changes. –Tim Pote Jun 18 '12 at 17:08 add a comment| Not the answer you're looking for? Next, I tried to pass in a command via variable and have it working with ls "foo" but am having issues with ls "foo bar" -- note the space in the navigate here And if you want the exit code of your cmd (here a modification in the case of if the cmd stdout nothing) 1 cmd() { curl -s -v http://www.google.fr; } 2

eval "$( dummy 2> >(setval errval) > >(setval stdval); <<<"$?" setval retval; )" echo "std out is : |$stdval| std err is : |$errval| return val is : |$retval|" share|improve this Bash Capture Stderr To Variable Test command: %> cat xx.sh #!/bin/bash echo stdout >&2 echo stderr which by itself does: %> ./xx.sh stdout stderr Now, print stdout, capture stderr to a variable, & log stdout to Mar 14 at 6:57 This question has been asked before and already has an answer.

after running the command: 1 command 2 status=$?

bad_command3 # Error message echoed to stderr, #+ and does not appear in $ERRORFILE. # These redirection commands also automatically "reset" after each line. #=======================================================================

Did Donald Trump call Alicia Machado "Miss Piggy" and "Miss Housekeeping"? asked 6 years ago viewed 31530 times active 5 years ago Visit Chat Linked 88 How to store standard error in a variable in a Bash script 15 Bash how do I'm guessing something like out=$(some_command) and err=$(some_command 2>&1 1>/dev/null)? –ntc2 Jun 19 '14 at 2:51 Done! his comment is here What does an 'ü' mean?

This site is not affiliated with Linus Torvalds or The Open Group in any way. Intuition behind Harmonic Analysis in Analytic Number Theory On THE other hand or on another hand? In other words: VAR=$((your-command-including-redirect) 2>&1) Since your command redirects stdout somewhere, it shouldn't interfere with stderr. I don't think there's an easy way to do it.

What is the sh -c command? The Woz Monitor Problem with using pause and onslide in one frame Do COB LEDs usually need electrically insulating from the heatsink? A simple visual puzzle to die for Are there any 'smart' ejection seats? I'll call your command banana.

The most basic shell grouping construct, that does nothing but group, is braces. If you want the last command's status, no problem -- it's in $? Can you think of a solution for this? I think that this is because $() launches a sub process which no longer has access to the file descriptor in /dev/fd which is owned by the parent process.

Skeletal formula for carbon with two double bonds more hot questions question feed lang-bsh about us tour help blog chat data legal privacy policy work here advertising info mobile contact us Well, then first you have to decide where you do want stdout to go: 1 output=$(command 2>&1 >/dev/null) # Save stderr, discard stdout. 2 output=$(command 2>&1 >/dev/tty) # Save stderr, send Then: { bout=$(banana); } 2>&1; declare -p bout >&2 will do as above, but will also display on the terminal (via stderr) the content of bout with the declare builtin: this

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