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Return Code Pipe Shell

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The temporary file may be read before it's written. 2. When jumping a car battery, why is it better to connect the red/positive cable first? So the 4>&- makes sure that the inner compound command will not inherit file descriptor four, and the 3>&- will not inherit file descriptor three, so command1 gets a 'cleaner', more bar will run only when command1 or foo succeeds.Random example:test -f ~/.config && echo "config already exists!" || touch ~/.configMy question is: Is there a straightforward way to pipe command1 into Source

parts won't be intermixed as long as the tag strings are under 507 bytes. how to snap several vertices to the same z.position Taxiing with one engine: Is engine #1 always used or do they switch? bash pipe share|improve this question asked May 17 '12 at 19:25 Mustafa Serdar Şanlı 13814 add a comment| 5 Answers 5 active oldest votes up vote 6 down vote accepted You Command substitution will capture whatever is written on standard out from the perspective of the commands inside it – but, since command2's output is going to file descriptor 4 as far http://unix.stackexchange.com/questions/14270/get-exit-status-of-process-thats-piped-to-another

Bash Pipestatus

Checking exit status of a command in bash scripting is essential. see more linked questions… Related 1068Check if a program exists from a Bash script389Redirect stderr and stdout in a Bash script786How can I redirect and append both stdout and stderr to foo will run only when command1 succeeds (exit code 0)2.

into a file at some appropriate point, and pick it up later.posted by flabdablet at 3:34 PM on November 24, 2007 Use ${PIPESTATUS[*]} in bash. foo_ret=$(cat "$foo_ret_file"; rm -f "$foo_ret_file") share|improve this answer edited Jan 15 '15 at 5:58 mikeserv 38.1k444114 answered Jun 3 '11 at 0:33 Gilles 388k757161166 1 When using the temporary file In this example, send netstat command output to grep command i.e. Pipestatus Sh That means someprog will inherit open file descriptor 3 and 4.

Bash - How to check the exit status of pipe comman... Ksh Pipestatus will still contain the return code of the second command in the pipe, because variable assignments, command substitutions, and compound commands are all effectively transparent to the return code of the Contents of table bigger than the rest of the text and also not centered Preserving Vertices Why isn't the religion of R'hllor, The Lord of Light, dominant? http://stackoverflow.com/questions/6871859/piping-command-output-to-tee-but-also-save-exit-code-of-command Yes once you know this, getting the right exit code is trivial !

Example: mysqldump -u $db_username -p $db_name | gzip -c > output.sql.gz One would just check the exit status of the above using : echo $? Bash Pipefail If the returned value from haconf is true, then the 'if' block will be executed and grep will read "$haconf_out", trying to match it against "Cluster already writable". For example, if I know that foo never produces a line with just digits, then I can just tack on the exit code: { foo; echo "$?"; } | awk '!/[^0-9]/ If you need to access it later use the export command: # my_cmd_that_fails; export RET_VAL=$? | postprocessor_that_succeeds # echo $RET_VALposted by puddpunk at 3:40 PM on November 24, 2007 SCDB is

  1. But this only allows you to see the error after the fact.posted by Steven C.
  2. Standard error (file descriptor 2) is not merged with standard output.
  3. fi Specifically speaking, you can run something like this: haconf_out=/path/to/some/temporary/file if haconf -makerw > "$haconf_out" 2>&1; then grep -iq "Cluster already writable" "$haconf_out" # ...
  4. But since I'm piping all the output to tee, I cannot access the return code of mvn clean install, so when I access $?
  5. It was not specified so I provided a qualified answer.
  6. Den Beste at 3:31 PM on November 24, 2007 I think I botched that syntax. "two ampersand into" isn't right, but I'm not sure what is.posted by Steven C.

Ksh Pipestatus

In #part3 file descriptor 3 was redirected to #part2. You cannot fiddle with the existing file descriptors, so stdin/out/err must not be touched (however you can introduce some new one temporarily) Additional assumptions. Bash Pipestatus From the Bash Reference Manual: The exit status of a pipeline is the exit status of the last command in the pipeline, unless the pipefail option is enabled (see The Set Zsh Pipestatus That's where bash store exit status of the recent command from a pipe.

asked 7 years ago viewed 83468 times active 18 days ago Visit Chat Linked 79 Piping command output to tee but also save exit code of command 2 piping output through http://1pxcare.com/return-code/return-code-157.html If someprog writes to file descriptor 3 then that will become the exit status. grouse: You've piqued my curiosity; The only question: What are the indices in the PIPESTATUS array? So, the question is, how can I get both $PIPESTATUS and assign the output to a variable at the same time? Ksh Pipefail

and you probably want to create a tempfile to avoid race conditions. I have something like this in my .bashrc, which gives me the exit status of every command in the last pipe I just ran, if anything is not 0: exportPROMPT_COMMAND="
_RES=\${PIPESTATUS[*]};
_RES_STR='';
forresin\$_RES;do
if[[(\$res>0)]];then
_RES_STR=\"[\$_RES]\";
fi;
done"

exportPS1="\n\u@\h\w\$_RES_STR\n\\$" Try exit_codes=$({ { foo; echo foo:"$?" >&3; } | { bar >/dev/null; echo bar:"$?" >&3; } } 3>&1) After this $exit_codes is usually foo:X bar:Y, but it could be bar:Y foo:X if have a peek here Not the answer you're looking for?

Why are copper cables round? Unset Pipefail Often, /tmp is the only place where a script is sure to be able to write files. Rather, you can simply run the pipe through bash -o pipefail -c "false | true" and if any piped command fails, echo $?

Why isn't the religion of R'hllor, The Lord of Light, dominant? ​P​i​ =​= ​3​.​2​ What would be your next deduction in this game of Minesweeper?

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 Browse other questions tagged bash pipe or ask your own question. to the command inverts the return code. Pipefail Sh exit $?

#!/bin/bash COMMAND1 . . .

So just have my_cmd_that_fails echo $? Something like this: { { { { someprog; echo $? >&3; } | filter >&4; } 3>&1; } | stdintoexitstatus; } 4>&1 I've checked this construct with dash version 0.5.5 and Don't you leave a file behind called foo-status? –Johan Jun 8 '11 at 18:39 @Johan: If you prefer my suggestion, don't hesitate to vote it up ;) In addition Check This Out Here is my solution: ((((someprog; echo $? >&3) | filter >&4) 3>&1) | (read xs; exit $xs)) 4>&1 echo $?

After a function returns, $? gives the exit status of the last command executed in the function. What in the world happened with my cauliflower? Is there any way to get at it? By using: VALUE=$(might_fail | piping; exit ${PIPESTATUS[0]}) I get want I wanted. –vaab Jun 23 '14 at 8:47 @vaab, that syntax looks really nice but I am confused on

This doesn't work if you need the return code from more than one of the pipe parts (but you could split the pipeline if the output isn't too large, as it