Generate a random salt from bash

bash-random-salt

#!/bin/bash 

[ $# -eq 0 ] && {
        echo "usage: salt <length>">&2
        exit
}
strings </dev/urandom | while read line; do
        echo $line | tr '\n\t ' $RANDOM:0:1 >> /tmp/.salt.$$
        salt=$(cat /tmp/.salt.$$)
        [ ${#salt} -ge $1 ] && salt=${salt:0:$1} && echo $salt && break
done
rm -f /tmp/.salt.$$