+ A string that specifies how the output of the select query is
+ going to be formated. Depending on the chosen select-mode,
+ several conversion specifiers are available and a different
+ default value for this option applies.
+
+ adu knows four different types of directives: string, id,
+ count and size. These are explained in more detail below.
+
+ The general syntax for string and id directives is %(name:a:w)
+ where \"name\" is the name of the directive, \"a\" specifies
+ the alignment and \"w\" is the width specifier which allows
+ to give a field width.
+
+ The alignment specifier is a single character: Either \"l\",
+ \"r\", or \"c\" may be given to specify left, right and
+ centered alignment respectively. The with specifier is a
+ positive integer. Both \"a\" and \"w\" are optional.
+
+ A string directive supported by adu is \"dirname\" which is
+ substituted by the name of the directory. It is available
+ if either user_list or global_list mode was selected via
+ --select-mode.
+
+ Examples:
+ Print dirname without any padding:
+
+ \"%(diname)\"
+
+ Center dirname in a 20 chars wide field:
+
+ \"%(dirname:c:20)\"
+
+ The other two types of directives, count and size, are used
+ for numbers. The syntax for these is %(name:a:w:u). The \"a\"
+ and the \"w\" specifier have the same meaning as for the string
+ and id directives. The additional \"u\" specifier selects a unit
+ in which the number that corresponds to the directive should
+ be formated. All three specifiers are optional.
+
+ Possible units are the characters of the set \" bkmgtBKMGT\"
+ specifying bytes, kilobytes, megabytes, gigabytes and
+ terabytes respectively. The difference between the lower and
+ the upper case variants is that the lower case specifiers
+ select 1024-based units while the upper case specifiers use
+ 1000 as the basis.
+
+ The whitespace character is like \"b\", but a space character
+ is printed instead of a unit.
+
+ Two more characters \"h\" and \"H\" (human-readable) are also
+ available that choose an appropriate unit depending on the
+ size of the number being printed.
+
+ An asterisk prepended to the unit specifier prevents the
+ unit from being printed. This is useful mainly for feeding
+ the output of adu to scripts that do not expect units.
+
+ In order to print a percent sign, use \"%%\". Moreover, adu
+ understands \"\\n\" and \"\\t\" and outputs a newline and a
+ tab character for these combinations respectively.
+
+ Examples:
+ Print size in gigabytes right-aligned:
+ \"%(size:r::G)\"
+
+ As before, but use 5 char wide field:
+ \"%(size:r5::G)\"
+
+ As before, but suppress trailing \"G\":
+ \"%(size:r5::*G)\"
+
+
+ The following list contains all directives known to adu,
+ together with their types, and for which modes each of
+ them may be used.
+
+ pw_name (string): user name. Available for user_list,
+ user_summary and for the header in user_list mode.
+
+ uid (id): user id. Available for user_list,
+ user_summary and for the header in user_list mode.
+
+ files (count): number of files. Available for all
+ modes.
+
+ dirname (string): name of the directory. Available
+ for user_list and global_list.
+
+ size (size): total size/ directory size. Available
+ for all modes.
+
+ dirs (count): number of directories. Available
+ for user_summary and global_summary.