Question : Scan text for a specific word and print surrounding text

How do I print text found prior to a selected word?

Scanning text for all occurrences of word "submarine" and printing
with 30 words (or n characters, if easier) before and after the word

blah blah blah submarine blah blah blah

Answer : Scan text for a specific word and print surrounding text

okay.

my $number_of=3;
if($line=~ m/(\s[^\s]+){1,$number_of}\s(submarine)(\s[^\s]+){1,$number_of}\s/gis){
    print "$&\n";
 }