#!/bin/bash

#
# Demonstrate a more complex regular expression to detect matching words in
# a file (one per line)
#

re='\<.{4,}[tl]ing\>'

while read -r line; do
    if [[ $line =~ $re ]]; then
        echo "$line"
    fi
done < <(shuf -n 100 /usr/share/dict/words)