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
+\fBhath\fR [\fBregexed|reduced|duped|diffed|listed|reversed\fR] [\fB\-hb\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.
+The \fIinput\fR (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
.IP \(bu
Find their associated PTR records.
.P
-Hath does just that. It takes as its input (via stdin, or a file with
-the -i parameter) a list of CIDR blocks.
+Hath does just that. It takes as its input (via stdin) a list of CIDR
+blocks.
.SH MODES
.P
Hath has several modes:
the input CIDR blocks. It's the default mode of operation.
.P
.nf
-.I $ 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])
+.I $ echo \(dq10.0.0.0/29 10.0.0.8/29\(dq | hath
+((10)\.(0)\.(0)\.(15|14|13|12|11|10|9|8|7|6|5|4|3|2|1|0))
.fi
.IP \(bu 2
\fBReduced\fR
the input, though.
.P
.nf
-.I $ hath reduced <<< \(dq10.0.0.0/24 10.0.1.0/24\(dq
+.I $ echo \(dq10.0.0.0/24 10.0.1.0/24\(dq | hath reduced
10.0.0.0/23
.fi
.IP \(bu 2
simply redundant.
.P
.nf
-.I $ hath duped <<< \(dq10.0.0.0/24 10.0.1.0/24\(dq
+.I $ echo \(dq10.0.0.0/24 10.0.1.0/24\(dq | hath duped
10.0.0.0/24
10.0.1.0/24
.fi
notation.
.P
.nf
-.I $ hath diffed <<< \(dq10.0.0.0/24 10.0.1.0/24\(dq
+.I $ echo \(dq10.0.0.0/24 10.0.1.0/24\(dq | hath diffed
-10.0.0.0/24
-10.0.1.0/24
+10.0.0.0/23
List the IP addresses contained within the given CIDRs.
.P
.nf
-.I $ hath listed <<< \(dq192.168.0.240/29\(dq
+.I $ echo 192.168.0.240/29 | hath listed
192.168.0.240
192.168.0.241
192.168.0.242
the given CIDRs.
.P
.nf
-.I $ hath reversed <<< \(dq198.41.0.4/30\(dq
+.I $ echo 198.41.0.4/30 | hath reversed
198.41.0.4: a.root-servers.net.
198.41.0.5:
198.41.0.6: rs.internic.net.
25 lookups in parallel:
.P
.nf
-.I $ hath reversed +RTS -N25 <<< \(dq198.41.0.4/24\(dq
+.I $ echo 198.41.0.4/24 | hath reversed +RTS -N25
198.41.0.4: a.root-servers.net.
198.41.0.5:
198.41.0.6: rs.internic.net.
\(pc\(pc\(pc
.fi
-.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, \fBlist\fR, \fBreverse\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).
+.IP \fB\-\-barriers\fR,\ \fB\-b\fR
+(regexed mode only) place barriers in front/back of the regex to
+prevent e.g. '127.0.0.1' from matching '127.0.0.100'. The downside is
+that the resulting regexp will match something that is not an IP
+address, and this messes up e.g. \fIgrep -o\fR.
+
+.P
+Without \fB\-\-barriers\fR, you can match things you shouldn't:
+
+.nf
+.I $ echo 127.0.0.100 | grep -P $(echo 127.0.0.1/32 | hath)
+127.0.0.100
+.fi
+
+.P
+Using \fB\-\-barriers\fR can prevent this:
+
+.nf
+.I $ echo 127.0.0.100 | grep -P $(echo 127.0.0.1/32 | hath -b)
+.I $ echo $?
+1
+.fi
+
+.P
+But, this may also cause the regex to match something that isn't an IP
+address:
+
+.nf
+.I $ echo x127.0.0.1x | grep -Po $(echo 127.0.0.1/32 | hath -b)
+x127.0.0.1x
+.fi