haskell@gentoo.org
Gentoo Haskell
Hath is a Haskell program for working with network blocks in CIDR
notation. When dealing with blocks of network addresses, there are a
few things that one usually wants to do with them:
* Create a regular expression matching the CIDR block(s). This is
because grep will throw up if you feed it CIDR.
* Combine small blocks into larger ones. For example, if you have two
consecutive \/24s, they might combine into a larger \/23.
* View the result of block combination in a useful way.
Hath has four modes to perform these functions:
[@Regexed@]
This computes a (Perl-compatible) regular expression matching
the input CIDR blocks. It's the default mode of operation.
[@Reduced@]
This combines small blocks into larger ones where possible, and
eliminates redundant blocks. The output should be equivalent to
the input, though.
[@Duped@]
Shows only the blocks that would be removed by reduce; that is, it
shows the ones that would get combined into larger blocks or are
simply redundant.
[@Diffed@]
Shows what would change if you used reduce. Uses diff-like
notation.
/Examples/:
Combine two \/24s into a \/23:
@
$ hath reduced <<< \"10.0.0.0\/24 10.0.1.0\/24\"
10.0.0.0/23
@
Create a perl-compatible regex to be fed to grep:
@
$ grep -P `hath regexed -i cidrs.txt` mail.log
@