CODEWITHSUNDEEP
bashnamed-pipes
Zachary Vance
Zachary Vance

Reputation: 860

How to make named pipes in bash

This program works great, but how do I go from supporting 2 files to supporting n files using the same [un]named pipe approach?

some_command \ 
    <(tar c --xattrs -C "$1" --pax-option="exthdr.name=%d/PaxHeaders/%f" . | xxd) \
    <(tar c --xattrs -C "$2" --pax-option="exthdr.name=%d/PaxHeaders/%f" . | xxd)

Upvotes: 0

Views: 137

Answers (1)

chepner
chepner

Reputation: 531135

Rather than using the process substitution syntax, create the named pipes explicitly. (Process substitution is a transient construct; you can't create them one at a time to save up for later use.)

declare -a pipes
for arg in "$@"; do
    new_pipe_name=pipe$((++i))
    pipes+=( "$new_pipe_name" )
    mkfifo "$new_pipe_name"
    tar c --xattrs -C "$arg" --pax-option="exthdr.name=%d/PaxHeaders/%f" . | 
      xxd > "$new_pipe_name" &
done

mycommand "${pipes[@]}"
rm "${pipes[@]}"

Upvotes: 2

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