例えば % perl -e 'system "sleep 1000"' | grep a | sort | uniq で % ps axo pid,pgid,command PID PGID COMMAND 26275 26275 -zsh 84326 84326 perl -e system "sleep 1000" 84327 84326 grep a 84328 84326 sort 84329 84326 uniq 84330 84326 sleep 100…