+Interactive mode
+----------------
+When the command enters the interactive mode, it shows the
+files and directories to be cleaned, and goes into its
+interactive command loop.
+
+The command loop shows the list of subcommands available, and
+gives a prompt "What now> ". In general, when the prompt ends
+with a single '>', you can pick only one of the choices given
+and type return, like this:
+
+------------
+ *** Commands ***
+ 1: clean 2: filter by pattern 3: select by numbers
+ 4: ask each 5: quit 6: help
+ What now> 1
+------------
+
+You also could say `c` or `clean` above as long as the choice is unique.
+
+The main command loop has 6 subcommands.
+
+clean::
+
+ Start cleaning files and directories, and then quit.
+
+filter by pattern::
+
+ This shows the files and directories to be deleted and issues an
+ "Input ignore patterns>>" prompt. You can input space-seperated
+ patterns to exclude files and directories from deletion.
+ E.g. "*.c *.h" will excludes files end with ".c" and ".h" from
+ deletion. When you are satisfied with the filtered result, press
+ ENTER (empty) back to the main menu.
+
+select by numbers::
+
+ This shows the files and directories to be deleted and issues an
+ "Select items to delete>>" prompt. When the prompt ends with double
+ '>>' like this, you can make more than one selection, concatenated
+ with whitespace or comma. Also you can say ranges. E.g. "2-5 7,9"
+ to choose 2,3,4,5,7,9 from the list. If the second number in a
+ range is omitted, all remaining patches are taken. E.g. "7-" to
+ choose 7,8,9 from the list. You can say '*' to choose everything.
+ Also when you are satisfied with the filtered result, press ENTER
+ (empty) back to the main menu.
+
+ask each::
+
+ This will start to clean, and you must confirm one by one in order
+ to delete items. Please note that this action is not as efficient
+ as the above two actions.
+
+quit::
+
+ This lets you quit without do cleaning.
+
+help::
+
+ Show brief usage of interactive git-clean.
+