Re: Patternmatching IPaddresses

[rjt]

You might try explicitly matching either the beginning of the string or a space with (^|\s):

use 5.014; # For /r regex modifier

print s/(^|\s)\d+\.\d+/$1X.X/gr for <DATA>;
 
__DATA__
10.128.99.190 10.128.100.100
1.1.1.1 2.2.2.2
3.3.3.3 4.4.4.4
100.100.100.100 200.200.200.200

Note that if your Perl is older than 5.014, and hence you can not use the /r modifier, you can replace the print() statement with this:

    print map { s/(^|\s)\d+\.\d+/$1X.X/g; $_ } <DATA>;

If you need stricter validation of your input data, the following regexp will only match lines that have two IP addresses and nothing else:

    s/^\d+\.\d+\.(\d+\.\d+) \d+\.\d+\.(\d+\.\d+)$/X.X.$1 X.X.$2/;

Note that the /g modifier is not necessary in this case as the regexp covers the entire string.