v0.2.3

ADDED:
* Additional diagram under table subcommand for the IPv6 CIDR segments

ACKNOWLEDGEMENTS

@@ -0,0 +1,8 @@
+The "IPv6 Segment Reference Diagram" output as rendered in the `table`
+subcommand is from:
+	https://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing
+as fetched on April 07, 2025.
+It is licensed under Creative Commons "CC BY-SA 4.0";
+see:
+	https://creativecommons.org/licenses/by-sa/4.0/
+	https://creativecommons.org/licenses/by-sa/4.0/legalcode.en)

cmd/subnetter/_tpl/table.tpl

@@ -5,7 +5,7 @@
 	{{- if $opts.Plain }}
 IPV4:
 	{{- else }}
-{{- bold "IPv4:"}}
+{{- bold "IPv4:" }}
 	{{- end }}
 	{{- if $opts.Legacy }}
 		{{- if $opts.Plain }}
@@ -47,13 +47,268 @@ IPV4:
 {{- end }}
 
 {{- if not $opts.NoIpv6 }}
-
-{{- if $opts.Plain }}
-IPV6:
-{{- else }}
-{{ bold "IPv6:"}}
-{{- end }}
 	{{- if $opts.Plain }}
+IPV6:
+	{{- else }}
+{{ bold "IPv6:"}}
+	{{- end }}
+	{{- if not $opts.NoIpv6Seg }}
+		{{- if $opts.Plain }}
+	IPv6 Segment Reference Diagram:
+			{{- if $opts.VertSeg }}
+
+		Example:	2001:0db8:0123:4567:89ab:cdef:1234:5678
+				{{- if not $opts.VertInvert }}
+		2								4
+		0								8
+		0								12
+		1								16
+		:
+			0							20
+			d							24
+			b							28
+			8							32
+			:
+				0						36
+				1						40
+				2						44
+				3						48
+				:
+					4					52
+					5					56
+					6					60
+					7					64
+					:
+						8				68
+						9				72
+						a				76
+						b				80
+						:
+							c			84
+							d			88
+							e			92
+							f			96
+							:
+								1		100
+								2		104
+								3		108
+								4	 	112
+								:
+									5	116
+									6	120
+									7	124
+									8	127 or 128
+				{{- else }}
+		4 ____ 2
+		8 ____ 0
+		12 ___ 0
+		16 ___ 1
+		   ___ :
+		20 _____ 0
+		24 _____ d
+		28 _____ b
+		32 _____ 8
+		   _____ :
+		36 _______ 0
+		40 _______ 1
+		44 _______ 2
+		48 _______ 3
+		   _______ :
+		52 _________ 4
+		56 _________ 5
+		60 _________ 6
+		64 _________ 7
+		   _________ :
+		68 ___________ 8
+		72 ___________ 9
+		76 ___________ a
+		80 ___________ b
+		   ___________ :
+		84 _____________ c
+		88 _____________ d
+		92 _____________ e
+		96 _____________ f
+		   _____________ :
+		100 ______________ 1
+		104 ______________ 2
+		108 ______________ 3
+		112 ______________ 4
+		    ______________ :
+		116 ________________ 5
+		120 ________________ 6
+		124 ________________ 7
+		127 ________________ (8)
+		128 ________________ (8)
+				{{- end }}
+			{{- else }}
+
+		2001:0db8:0123:4567:89ab:cdef:1234:5678
+		|||| |||| |||| |||| |||| |||| |||| ||||
+		|||| |||| |||| |||| |||| |||| |||| |||128
+		|||| |||| |||| |||| |||| |||| |||| |||127
+		|||| |||| |||| |||| |||| |||| |||| ||124
+		|||| |||| |||| |||| |||| |||| |||| |120
+		|||| |||| |||| |||| |||| |||| |||| 116
+		|||| |||| |||| |||| |||| |||| |||112
+		|||| |||| |||| |||| |||| |||| ||108
+		|||| |||| |||| |||| |||| |||| |104
+		|||| |||| |||| |||| |||| |||| 100
+		|||| |||| |||| |||| |||| |||96
+		|||| |||| |||| |||| |||| ||92
+		|||| |||| |||| |||| |||| |88
+		|||| |||| |||| |||| |||| 84
+		|||| |||| |||| |||| |||80
+		|||| |||| |||| |||| ||76
+		|||| |||| |||| |||| |72
+		|||| |||| |||| |||| 68
+		|||| |||| |||| |||64
+		|||| |||| |||| ||60
+		|||| |||| |||| |56
+		|||| |||| |||| 52
+		|||| |||| |||48
+		|||| |||| ||44
+		|||| |||| |40
+		|||| |||| 36
+		|||| |||32
+		|||| ||28
+		|||| |24
+		|||| 20
+		|||16
+		||12
+		|8
+		4
+			{{- end }}
+		{{- else }}
+	{{ bold "IPv6 Segment Reference Diagram:" }}
+			{{- if $opts.VertSeg }}
+
+		{{ bold "Example:"}}	2001:0db8:0123:4567:89ab:cdef:1234:5678
+				{{- if not $opts.VertInvert }}
+		2								4
+		0								8
+		0								12
+		1								16
+		:
+			0							20
+			d							24
+			b							28
+			8							32
+			:
+				0						36
+				1						40
+				2						44
+				3						48
+				:
+					4					52
+					5					56
+					6					60
+					7					64
+					:
+						8				68
+						9				72
+						a				76
+						b				80
+						:
+							c			84
+							d			88
+							e			92
+							f			96
+							:
+								1		100
+								2		104
+								3		108
+								4	 	112
+								:
+									5	116
+									6	120
+									7	124
+									8	127 or 128
+				{{- else }}
+		4 ━━━━ 2
+		8 ━━━━ 0
+		12 ━━━ 0
+		16 ━━━ 1
+		   ━━━ :
+		20 ━━━━━ 0
+		24 ━━━━━ d
+		28 ━━━━━ b
+		32 ━━━━━ 8
+		   ━━━━━ :
+		36 ━━━━━━━ 0
+		40 ━━━━━━━ 1
+		44 ━━━━━━━ 2
+		48 ━━━━━━━ 3
+		   ━━━━━━━ :
+		52 ━━━━━━━━━ 4
+		56 ━━━━━━━━━ 5
+		60 ━━━━━━━━━ 6
+		64 ━━━━━━━━━ 7
+		   ━━━━━━━━━ :
+		68 ━━━━━━━━━━━ 8
+		72 ━━━━━━━━━━━ 9
+		76 ━━━━━━━━━━━ a
+		80 ━━━━━━━━━━━ b
+		   ━━━━━━━━━━━ :
+		84 ━━━━━━━━━━━━━ c
+		88 ━━━━━━━━━━━━━ d
+		92 ━━━━━━━━━━━━━ e
+		96 ━━━━━━━━━━━━━ f
+		   ━━━━━━━━━━━━━ :
+		100 ━━━━━━━━━━━━━━ 1
+		104 ━━━━━━━━━━━━━━ 2
+		108 ━━━━━━━━━━━━━━ 3
+		112 ━━━━━━━━━━━━━━ 4
+		    ━━━━━━━━━━━━━━ :
+		116 ━━━━━━━━━━━━━━━━ 5
+		120 ━━━━━━━━━━━━━━━━ 6
+		124 ━━━━━━━━━━━━━━━━ 7
+		127 ━━━━━━━━━━━━━━━━ (8)
+		128 ━━━━━━━━━━━━━━━━ (8)
+				{{- end }}
+			{{- else }}
+
+		{{ bold "2001:0db8:0123:4567:89ab:cdef:1234:5678" }}
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃128
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃127
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃124
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃120
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ 116
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃112
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃108
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃104
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ 100
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃96
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃92
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃88
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ 84
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃80
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃76
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃72
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃┃ 68
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃┃64
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃┃60
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ ┃56
+		┃┃┃┃ ┃┃┃┃ ┃┃┃┃ 52
+		┃┃┃┃ ┃┃┃┃ ┃┃┃48
+		┃┃┃┃ ┃┃┃┃ ┃┃44
+		┃┃┃┃ ┃┃┃┃ ┃40
+		┃┃┃┃ ┃┃┃┃ 36
+		┃┃┃┃ ┃┃┃32
+		┃┃┃┃ ┃┃28
+		┃┃┃┃ ┃24
+		┃┃┃┃ 20
+		┃┃┃16
+		┃┃12
+		┃8
+		4
+			{{- end }}
+		{{- end }}
+	{{- end }}
+
+
+	{{- if $opts.Plain }}
+
 	CIDR:
 	{{- else }}
 	{{ bold "CIDR:" }}

cmd/subnetter/args.go

@@ -83,12 +83,15 @@ type SplitSubnetArgs struct {
 }
 
 type TableArgs struct {
-	Notes    bool `short:"n" long:"notes" description:"Include notes about prefixes (as a separate table)."`
+	Notes      bool `short:"n" long:"notes" description:"Include notes about prefixes (as a separate table)."`
-	Legacy   bool `short:"l" long:"legacy" description:"Include legacy/obsolete/deprecated information (as separate table(s))."`
+	Legacy     bool `short:"l" long:"legacy" description:"Include legacy/obsolete/deprecated information (as separate table(s))."`
-	Plain    bool `short:"p" long:"plain" description:"Show plain table output instead of unicode."`
+	Plain      bool `short:"p" long:"plain" description:"Show plain table output instead of unicode."`
-	NoV4Mask bool `short:"M" long:"no-mask" description:"Do not include netmasks for IPv4."`
+	NoV4Mask   bool `short:"M" long:"no-mask" description:"Do not include netmasks for IPv4."`
-	NoIpv6   bool `short:"4" long:"ipv4" description:"Only show IPv4 table(s)."`
+	NoIpv6     bool `short:"4" long:"ipv4" description:"Only show IPv4 table(s)."`
-	NoIpv4   bool `short:"6" long:"ipv6" description:"Only show IPv6 table(s)."`
+	NoIpv4     bool `short:"6" long:"ipv6" description:"Only show IPv6 table(s)."`
+	NoIpv6Seg  bool `short:"D" long:"no-ipv6-seg" description:"Do not show the IPv6 Segment Reference Diagram (ignored if -4/--ipv4 is specified)."`
+	VertSeg    bool `short:"V" long:"vert-ipv6-seg" description:"If specified, display the IPv6 Segment Reference Diagram vertically-aligned instead of horizontally."`
+	VertInvert bool `short:"I" long:"vert-invert" description:"When printing a vertical-aligned IPv6 Segment Reference Diagram, flip so the prefix length is on the left. This takes up less width and is recommended for smaller terminals, and may be easier to read in general."`
 }
 
 type CheckArgs struct {