generate a strong password without string delimiters in it

gen-pass.sh

#!/usr/bin/env bash

# generate a strong password without shell special characters
# defaults to 32 characters, overridden to a number passed as first arg
# uses xclip to copy to clipboard
# uses zenity to alert to desktop (from gnome-run-prompt)

  gen_pass_length=32
  if [ $# -eq 1 ]; then
    gen_pass_length="$1"
  fi

  # tinfoil hat:
  # prevent use of a cached random seed
  rm -f ~/.rnd

  # 999 - generate plenty of chars
  # 2>/dev/null - suppress 'could not write to ~/.rnd'
  # tr - whitelist provided octal character list.
  #   -c, -C, --complement
  #         use the complement of SET1
  #   -d, --delete
  #         delete characters in SET1, do not translate
  #   -s, --squeeze-repeats
  #         replace each input sequence of a repeated character that is listed
  #         in SET1 with a single occurrence of that character
  # head -c - num of chars
  # tee /dev/tty - output to terminal as well as copy to clipboard (xclip)
  #
  # Generate custom blacklist using:
  # http://www.unit-conversion.info/texttools/octal/

  charset='\041-\047\050-\057\060-\067\070-\077\100-\107\110-\117\120-\127\130-\137\140-\147\150-\157\160-\167\170-\176'

  # Exclude: "'`$&|:@;<>#
  blacklist='\042\047\140\044\046\174\072\100\073\074\076\043'

  # sample enough chars from the end of our random string
  # just for fun
  sample_size=$(( $gen_pass_length * 3 ))

  openssl rand 999 2>/dev/null | \
  tr -dC "$charset" | tr -d "$blacklist" | tr -s "$charset" | tail -c"$sample_size" | head -c"$gen_pass_length" | \
  tee /dev/tty | xclip -selection c

  gen_pass_msg='copied to clipboard'

  # Disabled check for terminal because approach doesn't work for xfce run-prompt.
  # if [ -t 1 ]; then
  #   # shell
  #   echo $'\n'$gen_pass_msg
  # else
    # desktop
    zenity --info --title='Password Generator' --text="$gen_pass_msg" --width=200 2>/dev/null
  # fi

  # tinfoil hat:
  rm -f ~/.rnd