Your string looks like
" cat mat rat pat\n", you wanna match the word 'cat' and not 'cater' or 'cats' or 'Catrina' for example, so your regex has to account for matching the word cat bounded by spaces or non word characters.. So you have many likely regex constructions to pick from (not including the
look-ahead or look-behind assertions or the
backtracking or the
backreferences):
$string =~ /\bcat\b/
$string =~ /\Wcat\W/
$string =~ /\scat\s/
If you don't mind the letter-case of the word then you can use the i switch as in <c>m/\bcat\b/i<c>, read
perlretut for a tutorial on regular expressions..
Update: another interesting read is 7 Stages of Regex Users...
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