prime/prime.sh

   1 #!/bin/bash
   2 #
   3 # Check if a number is prime (brute force)
   4 #
   5 # Luiz Fernando N. Capitulino
   6 # <lcapitulino@gmail.com>
   7
   8 is_prime()
   9 {
  10         local i
  11         local res
  12         local number=$1
  13         local max=$((${number} - 1))
  14
  15         for ((i = 2; i < $max; i++)); do
  16                 res=$(($number % $i))
  17                 if [ $res -eq 0 ]; then
  18                         return 0
  19                 fi
  20         done
  21
  22         return 1
  23 }
  24
  25 if [ $# -ne 1 ]; then
  26         echo "usage: prime.sh < number >"
  27         exit 1
  28 fi
  29
  30 is_prime $1
  31 if [ $? -eq 1 ]; then
  32         echo is prime
  33         ret=1
  34 else
  35         echo is not prime
  36         ret=0
  37 fi
  38
  39 exit $ret