All GNU Mailutils programs understand a common subset of options.
The output of this option consists of three major parts. First, a usage synopsis is displayed. For example:
Usage: sieve [OPTION...] SCRIPT GNU sieve -- a mail filtering tool
The first line tells that the sieve utility takes any number of options (brackets indicate optional part) and a single mandatory argument (‘SCRIPT’). The second lines summarizes the purpose of the utility.
Following this header is an option summary. It consists of two columns:
-c, --compile-only Compile script and exit -d, --debug[=FLAGS] Debug flags -e, --email=ADDRESS Override user email address
The leftmost column contains a comma-separated list of option names. Short options are listed first. The options are ordered alphabetically. Arguments, if any, are specified after the last option name in the list, so that, e.g. the option ‘-e’ in the example above requires an argument: ‘-e ADDRESS’. Optional arguments are enclosed in square brackets, as in --debug option in the example above.
The rightmost column contains a short description of the option purpose.
The last part of --help output contains some additional notices and lists the email address for reporting bugs.
Usage: sieve [-cv?V] [--compile-only] [--debug[=FLAGS]] [--email=ADDRESS] SCRIPT
The exact formatting of the output produced by these two options is configurable. See Usage Vars, for a detailed descriptions of it.
The following command line options affect parsing of configuration files. Here we provide a short summary, the next section will describe them in detail.