Domain Sorter

Here’s a Bash and Perl script for sorting domains and subdomains.

Command:

$ cat filename | perl -ple'$_=join".",reverse split/\./' | sort | perl -ple'$_=join".",reverse split/\./'

What’s in the domains.txt?

$ cat domains.txt
domain.com
abc.com
xyz.com
bbb.com
mail.gmail.com
ess.sfss.org
csub.edu
gmail.com

Result:

$ cat domains.txt | perl -ple'$_=join".",reverse split/\./' | sort | perl -ple'$_=join".",reverse split/\./'
abc.com
bbb.com
domain.com
gmail.com
mail.gmail.com
xyz.com
csub.edu
ess.sfss.org

You can also pipe the result to another file.

$ cat filename | perl -ple'$_=join".",reverse split/\./' | sort | perl -ple'$_=join".",reverse split/\./' > output.txt

Source.