= Bash Process Substitution =

<<TableOfContents>>

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== Process Substitutions ==

To use the output of a command as a file, use process subsitution.

To provide a command as an input file to another command, try:

{{{
cat <(date)
}}}

This grammar becomes more useful when multiple commands are used for input.

{{{
cat <(date) <(date) <(date)
}}}

To provide a command as an output file to another command, try:

{{{
curl --output >(cat) www.example.com
}}}

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== Redirection ==

Like any other file, a process substitution can be [[Bash/Redirection|redirected]] into a command.

{{{
cat < <(date)
}}}

For the most part, this is equivalent to using a [[Bash/Pipeline|pipeline]]. The `STDOUT` of `commanda` is piped into the `STDIN` of `cat(1)`. The difference is that multiple commands can be piped in.

Similarly, output can be redirected into a process substitution.

{{{
date > >(cat)
}}}

Again, this is generally equivalent to using a pipeline. The difference is that `STDOUT` and `STDERR` can be redirected separately.

{{{
date > >(cat) 2> >(cat)
}}}



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