.TH hath 1

.SH NAME
hath \- Manipulate network blocks in CIDR notation

.SH SYNOPSIS

\fBhath\fR [\fBregexed|reduced|duped|diffed\fR] [\fB\-h\fR] [\fB-i \fIFILE\fR] \fI<input>\fR

.SH INPUT

.P
The \fIinput\fR (default: stdin) should be a list of CIDR blocks,
separated by whitespace. Empty lines will be ignored, but otherwise,
malformed entries will cause an error to be displayed.

.SH DESCRIPTION

.P
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:

.IP \[bu] 2
Create a regular expression matching the CIDR block(s). This is
because grep will throw up if you feed it CIDR.

.IP \[bu]
Combine small blocks into larger ones. For example, if you have two
consecutive /24s, they might combine into a larger /23.

.IP \[bu]
View the result of block combination in a useful way.

.P
Hath does just that. It takes as its input (via stdin, or a file with
the -i parameter) a list of CIDR blocks.

.SH MODES

.P
Hath currently has four modes:

.IP \[bu] 2
\fBRegexed\fR

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

.nf
.B $ hath <<< \(dq10.0.0.0/24 10.0.1.0/24\(dq
([^\.0-9](10)\.(0)\.(0)\.(0)[^\.0-9]|[^\.0-9](10)\.(0)\.(1)
\.(0)[^\.0-9])

.IP \[bu]
\fBReduced\fR

This combines small blocks into larger ones where possible, and
eliminates redundant blocks. The output should be equivalent to
the input, though.

.nf
.B $ hath reduced <<< \(dq10.0.0.0/24 10.0.1.0/24\(dq
10.0.0.0/23

.IP \[bu]
\fBDuped\fR

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.

.nf
.B $ hath duped <<< \(dq10.0.0.0/24 10.0.1.0/24\(dq
10.0.0.0/24
10.0.1.0/24

.IP \[bu]
\fBDiffed\fR

Shows what would change if you used reduce. Uses diff-like
notation.

.nf
.B $ hath diffed <<< \(dq10.0.0.0/24 10.0.1.0/24\(dq
-10.0.0.0/24
-10.0.1.0/24
+10.0.0.0/23

.P
Each of the modes also supports a present-tense flavor; the following
are equivalent to their counterparts: \fBregex\fR, \fBreduce\fR,
\fBdupe\fR, \fBdiff\fR.

.SH OPTIONS

.IP \fB\-\-input\fR,\ \fB\-i\fR
Specify the input file containing a list of CIDRs, rather than using
stdin (the default).