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gen_string.sh (1881B)

      1 #!/bin/sh
      2 #
      3 # script
      4 
      5 DICT='/usr/share/dict/british-english'
      6 LENGTH_ERROR='String length must be a number between 1 and 64.'
      7 
      8 is_integer() {
      9     case "${1}" in
     10         (*[!0123456789]*) return 1 ;;
     11         ('')              return 1 ;;
     12         (*)               return 0 ;;
     13     esac
     14 }
     15 
     16 main() {
     17     while :; do
     18         # get string type
     19         printf '%s\n' 'Type of string (0 = random, 1 = phrase)?: '
     20         read -r string_type
     21         # incorrect input
     22         { [ ! "${string_type}" = '0' ] && [ ! "${string_type}" = '1' ] ; } && printf '%s\n' 'String type must be a number between 0 and 1.' && continue
     23         break
     24     done
     25 
     26     # get string length
     27     while :; do
     28         printf '%s\n' "If you're generating a phrase, it's recommended to use a middling length, because it's very time consuming or even impossible to generate a phrase if the length is very low or very high."
     29         printf '%s\n' 'Length of string (1-64)?: '
     30         read -r length
     31         # test whether input is number
     32         ! is_integer "${length}" && printf '%s\n' "${LENGTH_ERROR}" && continue
     33         # test whether input is within range
     34         { [ "${length}" -lt 1 ] || [ "${length}" -gt 64 ] ; } && printf '%s\n' "${LENGTH_ERROR}" && continue
     35         break
     36     done
     37 
     38     # generate string
     39     string=''
     40     # generate random string via /dev/urandom and tr
     41     if [ "${string_type}" = '0' ]; then
     42         string="$(</dev/urandom tr -dc 'A-Za-z0-9!"#$%&'\''()*+,-./:;<=>?@[\]^_`{|}~' | head -c "${length}"; printf '\n')"
     43         printf '%s\n' "${string}"
     44     # generate random phrase by pulling words from dictionary
     45     elif [ "${string_type}" = '1' ]; then
     46         while :; do
     47             string="$(grep -v "'s\|[[:upper:]]" "${DICT}" | shuf -n 4 | tr -d '\n')"
     48             [ ${#string} -eq "${length}" ] && printf '%s\n' "${string}" && break
     49         done
     50     fi
     51 
     52     return 0
     53 }
     54 
     55 main "${@}"