GNU Info

(bashref.info)Process Substitution

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Enter node , (file) or (file)node

Process Substitution
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   Process substitution is supported on systems that support named
pipes (FIFOs) or the `/dev/fd' method of naming open files.  It takes
the form of
     <(LIST)

or
     >(LIST)

The process LIST is run with its input or output connected to a FIFO or
some file in `/dev/fd'.  The name of this file is passed as an argument
to the current command as the result of the expansion.  If the
`>(LIST)' form is used, writing to the file will provide input for
LIST.  If the `<(LIST)' form is used, the file passed as an argument
should be read to obtain the output of LIST.  Note that no space may
appear between the `<' or `>' and the left parenthesis, otherwise the
construct would be interpreted as a redirection.

   When available, process substitution is performed simultaneously with
parameter and variable expansion, command substitution, and arithmetic
expansion.