+description:
+ 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.