@hackage hath0.5.7

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.

• List them.

Hath has several 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.

• Listed List the IP addresses contained within the given CIDRs.

Examples:

Compute a (Perl-compatible) regular expression matching the input CIDR blocks. It's the default mode of operation.

$ echo "10.0.0.0/29 10.0.0.8/29" | hath
((10).(0).(0).(15|14|13|12|11|10|9|8|7|6|5|4|3|2|1|0))

Combine two /24s into a /23:

$ echo "10.0.0.0/24 10.0.1.0/24" | hath reduced
10.0.0.0/23

List the addresses in 192.168.0.240/29:

$ echo 192.168.0.240/29 | hath listed
192.168.0.240
192.168.0.241
192.168.0.242
192.168.0.243
192.168.0.244
192.168.0.245
192.168.0.246
192.168.0.247

The command-line syntax and complete set of options are documented in the man page.