user-tools/awk-cut

   1 #!/bin/bash
   2
   3 true <<EOF
   4 =pod
   5
   6 =head1 NAME
   7
   8 awk-cut - Select fields from input stream with awk
   9
  10 =head1 SYNOPSIS
  11
  12 awk-cut [B<COLUMNS-SPEC>]
  13
  14 Where B<COLUMNS-SPEC> is a variation of these:
  15
  16 =over 8
  17
  18 =item B<COLUMN>-
  19
  20 =item -B<COLUMN>
  21
  22 =item B<COLUMN>-B<COLUMN>
  23
  24 =item B<COLUMN>[,B<COLUMN>[,B<COLUMN>[,...]]]
  25
  26 =back
  27
  28 =head1 SEE ALSO
  29
  30 cut.awk(1)
  31
  32 =cut
  33
  34 EOF
  35
  36
  37 shopt -s extglob
  38
  39 awk-cut()
  40 {
  41         local expr
  42         local narg=0
  43
  44         for colspec
  45         do
  46                 if [ $narg != 0 ]
  47                 then
  48                         expr=$expr"printf \"%s\", RS;"
  49                 fi
  50
  51                 local x=''
  52                 local y=''
  53
  54                 case "$colspec" in
  55                 +([0-9])-)
  56                         x=${colspec:0:-1}
  57                         y=NF
  58                         ;;
  59                 -+([0-9]))
  60                         x=0
  61                         y=${colspec:1}
  62                         ;;
  63                 +([0-9])-+([0-9]))
  64                         x=${colspec%%-*}
  65                         y=${colspec##*-}
  66                         ;;
  67                 [0-9]*([0-9,]))
  68                         expr=$expr"N=0; split(\"$colspec\", A, /,/); for(X in A){printf(\"%s%s\", N==0 ? \"\" : OFS, \$A[X]); N++};"
  69                         ;;
  70                 *)
  71                         echo "Invalid column spec: $colspec" >&2
  72                         ;;
  73                 esac
  74
  75                 if [ -n "$x" ]
  76                 then
  77                         expr=$expr"for(F=$x;F<=$y;F++) printf(\"%s%s\", F==$x ? \"\" : OFS, \$F);"
  78                 fi
  79
  80                 narg=$((narg + 1))
  81         done
  82
  83         awk "{ $expr printf \"%s\", RS; }"
  84 }
  85
  86 awk-cut "$@"