user-tools/pipecmd

   1 #!/bin/bash
   2
   3 true <<'EOF'
   4 =pod
   5
   6 =head1 NAME
   7
   8 pipecmd - Run a command and pipe its output to an other one
   9
  10 =head1 SYNOPSIS
  11
  12 pipecmd I<CMD_1> [I<ARGS>] -- I<CMD_2> [I<ARGS>]
  13
  14 =head1 DESCRIPTION
  15
  16 Equivalent to this shell command:
  17
  18  CMD_1 | CMD_2
  19
  20 The first command's (I<CMD_1>) arguments can not contain a double-dash (C<-->),
  21 because it's the command separator for pipecmd(1).
  22 However, since only a total of 2 commands are supported,
  23 arguments for I<CMD_2> may contain double-dash(es).
  24
  25 You can chain pipecmd(1) commands together to get a pipeline equivalent to
  26 C<CMD_1 | CMD_2 | CMD_3>, like:
  27
  28  pipecmd CMD_1 -- pipecmd CMD_2 -- CMD_3
  29
  30 =head1 RATIONALE
  31
  32 It's sometimes more convenient to don't involve shell command-line parser.
  33
  34 =head1 SEE ALSO
  35
  36 pipexec(1)
  37
  38 =cut
  39
  40 EOF
  41
  42
  43 set -e
  44 set -o pipefail
  45 set -u
  46
  47 if [ $# = 0 ]
  48 then
  49         pod2text "$0" >&2
  50         exit 1
  51 fi
  52 if [ "$1" = --help ]
  53 then
  54         pod2text "$0"
  55         exit 0
  56 fi
  57
  58 cmd_n=1
  59 declare -a cmd_1=()
  60 declare -a cmd_2=()
  61
  62 while [ $# != 0 ]
  63 do
  64         if [ ".$1" = '.--' -a $cmd_n == 1 ]
  65         then
  66                 cmd_n=2
  67         else
  68                 eval "cmd_${cmd_n}+=(\"\$1\")"
  69         fi
  70         shift
  71 done
  72
  73 "${cmd_1[@]}" | "${cmd_2[@]}"