Bash print stderr only, not stdout

LinuxBash

Linux Problem Overview

I want to lint a file, and print the stderr (error message), but do not print the stdout (saying the file is OK).

php -l "foo/bar.php"
  • If there are no errors, it prints a "No errors" message to stdout.
  • If there are errors, it prints a detailed message to stderr. I want only this one.

I figure it will be some magic with >&, but I never understood how those work.

What I want is to consume all stdout, keep stderr.

(Sorry if this is dulicate, but I haven't found any question exactly about this)

Linux Solutions

Solution 1 - Linux

Just send the stdout to null:

cmd > /dev/null

This retains stderr, but suppresses stdout.

Solution 2 - Linux

You can use:

php -l "foo/bar.php" 2>&1 > /dev/null

i.e. redirect stderr to stdout and stdout to /dev/null in order to get only stderr on your terminal.

Solution 3 - Linux

> If there are no errors, it prints a "No errors" message to stdout. > If there are errors, it prints a detailed message to stderr. I want only this one.

This would print the error message if one is sent or No error. if empty.

error=$(php -l "foo/bar.php" 2>&1 >/dev/null)
[[ -z $error ]] && error="No error."
echo "$error"
Categories
Recommended Linux Solutions
Recommended Bash Solutions

Previous Solution:

Attaching a process with pdb

PythonDebuggingPdb

Next Solution:

CardView background color states not being respected

AndroidAndroid Cardview

Attributions

All content for this solution is sourced from the original question on Stackoverflow.

The content on this page is licensed under the Attribution-ShareAlike 4.0 International (CC BY-SA 4.0) license.

Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionMightyPorkView Question on Stackoverflow
Solution 1 - LinuxnneonneoView Answer on Stackoverflow
Solution 2 - LinuxanubhavaView Answer on Stackoverflow
Solution 3 - LinuxkonsoleboxView Answer on Stackoverflow