For example
echo "aaa" |& cat
What does |& mean here?
Is there a website recommended to look up those? Since most search engines can't support searching special characters.
4 Answers
From man 1 bash, section Pipelines:
[time [-p]] [ ! ] command [ [|⎪|&] command2 ... ]
If |& is used,
command's standard error, in addition to its standard output, is connected tocommand2's standard input through the pipe
So it is just like the pipe operator |, but piping both standard output and standard error.
answered Feb 13, 2016 at 20:36
-
3@BallpointBen exactly. From gnu.org/software/bash/manual/bash.pdf:
If ‘|&’ is used, command1’s standard error, in addition to its standard output, is connected to command2’s standard input through the pipe; it is shorthand for 2>&1 |.– SantaXLCommented Nov 18, 2019 at 16:22 -
2@SantaXL It's worth noting that
|&isn't widely supported and you are better off using2>&1 |for greater shell support across different platforms and different Linux distributions. Commented Jun 29, 2023 at 1:20
This operator pipes both standard output and standard error from the left hand side to the right hand side.
The Bash reference manual has a comprehensive index of all operators where you can look up these operators.
If |& is used,
command_1’s standard error, in addition to it's standard output, is connected to command_2’s standard input through the pipe;
it is shorthand for 2>&1 |.
This implicit redirection of the standard error to the standard output is performed after any redirections specified by the command.
command1 |& command2 equal command1 2>&1 | command2
echo "aaa" |& catmay lead to-bash: syntax error near unexpected token `&'ifbash --versionisGNU bash, version 3.2.57(1)-release (x86_64-apple-darwin14).