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Process substitution allows a process’s input or output to be referred to using a filename. It takes the form of
The process list is run asynchronously, and its input or output
appears as a filename.
This filename is
passed as an argument to the current command as the result of 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
and the left parenthesis, otherwise the construct would be interpreted
as a redirection.
Process substitution is supported on systems that support named
pipes (FIFOs) or the /dev/fd method of naming open files.
When available, process substitution is performed simultaneously with parameter and variable expansion, command substitution, and arithmetic expansion.