git-column.1: clarify initial description, provide examples

When I read this man page I couldn't figure out what kind of input it
was referring to, or how input was being put into columns, or where I
should look for the syntax of the --mode option.

Signed-off-by: Frederick Eaton <frederik@ofb.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-column.txt

@@ -13,7 +13,10 @@ SYNOPSIS
 
 DESCRIPTION
 -----------
-This command formats its input into multiple columns.
+This command formats the lines of its standard input into a table with
+multiple columns. Each input line occupies one cell of the table. It
+is used internally by other git commands to format output into
+columns.
 
 OPTIONS
 -------
@@ -23,7 +26,7 @@ OPTIONS
 
 --mode=<mode>::
 	Specify layout mode. See configuration variable column.ui for option
-	syntax.
+	syntax in linkgit:git-config[1].
 
 --raw-mode=<n>::
 	Same as --mode but take mode encoded as a number. This is mainly used
@@ -43,6 +46,34 @@ OPTIONS
 --padding=<N>::
 	The number of spaces between columns. One space by default.
 
+EXAMPLES
+------
+
+Format data by columns:
+------------
+$ seq 1 24 | git column --mode=column --padding=5
+1      4      7      10     13     16     19     22
+2      5      8      11     14     17     20     23
+3      6      9      12     15     18     21     24
+------------
+
+Format data by rows:
+------------
+$ seq 1 21 | git column --mode=row --padding=5
+1      2      3      4      5      6      7
+8      9      10     11     12     13     14
+15     16     17     18     19     20     21
+------------
+
+List some tags in a table with unequal column widths:
+------------
+$ git tag --list 'v2.4.*' --column=row,dense
+v2.4.0  v2.4.0-rc0  v2.4.0-rc1  v2.4.0-rc2  v2.4.0-rc3
+v2.4.1  v2.4.10     v2.4.11     v2.4.12     v2.4.2
+v2.4.3  v2.4.4      v2.4.5      v2.4.6      v2.4.7
+v2.4.8  v2.4.9
+------------
+
 GIT
 ---
 Part of the linkgit:git[1] suite