This page contains some reqular expression for specific pattern matching purposes.
1. Match duplicate characters: /(.)\1/
2. Match duplicate words: /\b(\w+)\b.*\b\1\b/
3. var=`echo ${var//joshi/ketan}` – to replace substrings in a variable.
4. perl -F’/\|/’ -lane ‘BEGIN {$sum=0;} $sum+=$F[17]; END{print “$sum\n”;}’ *<file>* — use of perl lane.
