$string =~ s/PATTERN/REPLACEMENT_STRING/;
To do case-insensitive pattern matching, append an i to the substitution.
$string =~ s/PATTERN/REPLACEMENT_STRING/i;
If you want the replacement to operate on all possible matches instead of just the first match, append a g to the substitution.
$string =~ s/PATTERN/REPLACEMENT_STRING/g;To remove all substrings matching the pattern write:
$string =~ s/PATTERN//g;
Note that $string is changed after these operations!
# replace the first occurence of the word ID with "Identification"; $swiss_prot_line =~ s/ID/Identification/; # replace all occurences of BIU with Bar Ilan University $addresses =~ s/BIU/Bar Ilan University/g; # remove all spaces, tabs etc. from a sequence entry $seq =~ s/\s+//g;