user-tools/randstr

   1 #!/bin/bash
   2
   3 true <<'EOF'
   4
   5 =pod
   6
   7 =head1 NAME
   8
   9 randstr - Generate random string from a given set of characters and with a given length.
  10
  11 =head1 SYNOPSIS
  12
  13 randstr <LENGTH> [<CHARS>]
  14
  15 =head1 DESCRIPTION
  16
  17 B<CHARS> is a character set expression, see tr(1).
  18 Default B<CHARS> is C<[a-zA-Z0-9_]>
  19
  20 =cut
  21
  22 EOF
  23
  24 set -e
  25 set +o pipefail
  26 set -u
  27
  28
  29 if [ "$1" = --help ]
  30 then
  31         pod2text "$0"
  32         exit 0
  33 fi
  34
  35
  36 length=$1
  37 charset='[a-zA-Z0-9_]'
  38 if [ $# -gt 1 ]
  39 then
  40         charset=$2
  41 fi
  42
  43 cat /dev/urandom | tr --delete --complement "$charset" | { read -r -n $length str ; printf %s "$str"; }
  44
  45 exit ${PIPESTATUS[2]}