A shell script to validate the given text

This script will ensure that the given text contains only Alphabets and numeric characters

#!/bin/sh # validalAlphaNum - Ensures that input only consists of alphabetical # and numeric characters. validAlphaNum() { # validate arg: returns 0 if all upper+lower+digits, 1 otherwise # Remove all unacceptable chars compressed="$(echo $1 | sed -e 's/[^[:alnum:]]//g')" if [ "$compressed" != "$input" ] ; then return 1 else return 0 fi } # Sample usage of this function in a script echo -n "Enter input: " read input if ! validAlphaNum "$input" ; then echo "Your input must consist of only letters and numbers." >&2 exit 1 else echo "Input is valid." fi exit 0

Please let me know your doubts or questions. I will clarify them.