UNIX for Dummies Questions & Answers

  hello= gsdgsd sfdsg sgdsg sgdgdg
  world= gggg hhhh iiiii
  xxxx= pppp ppppp pppp

#!/bin/bash

while IFS="=" read v1 v2
do
        [[ "$v1" =~ ^[[:alpha:]]+$ ]] && echo "String: \"$v1\" is valid" || echo "String: \"$v1\" is invalid"
done < filename

while IFS="=" read v1 v2
do
        [[ "$v1" =~ ^[[:alpha:]]+$ ]] && echo "String: \"$v1\" is valid" || echo "String: \"$v1\" is invalid"
done < filename

while read line
do 
  case $line in 
    *[![:alpha:]]*=*) echo "String \"${line%%=*}\" is invalid"
  esac
done < infile