= Rake Command Line Usage

Rake is invoked from the command line using:

    % rake [options ...]  [VAR=VALUE ...]  [targets ...]

Options are:

[<tt><em>name</em>=<em>value</em></tt>]
    Set the environment variable <em>name</em> to <em>value</em>
    during the execution of the <b>rake</b> command.  You can access
    the value by using ENV['<em>name</em>'].

[<tt>--all</tt> (-A)]
    Used in combination with the -T and -D options, will force
    those options to show all the tasks, even the ones without comments.

[<tt>--backtrace</tt>{=_output_} (-n)]
    Enable a full backtrace (i.e. like --trace, but without the task
    tracing details). The _output_ parameter is optional, but if
    specified it controls where the backtrace output is sent. If
    _output_ is <tt>stdout</tt>, then backtrace output is directed to
    stardard output. If _output_ is <tt>stderr</tt>, or if it is
    missing, then the backtrace output is sent to standard error.

[<tt>--comments</tt>]
    Used in combination with the -W options to force the output to
    contain commented options only. This is the reverse of
    <tt>--all</tt>.

[<tt>--describe</tt> _pattern_ (-D)]
    Describe the tasks (matching optional PATTERN), then exit.

[<tt>--dry-run</tt> (-n)]
    Do a dry run.  Print the tasks invoked and executed, but do not
    actually execute any of the actions.

[<tt>--execute</tt> _code_ (-e)]
    Execute some Ruby code and exit.

[<tt>--execute-print</tt> _code_ (-p)]
    Execute some Ruby code, print the result, and exit.

[<tt>--execute-continue</tt> _code_ (-E)]
    Execute some Ruby code, then continue with normal task processing.

[<tt>--help</tt>  (-H)]
    Display some help text and exit.

[<tt>--jobs</tt> _number_  (-j)]
    Specifies the number of active concurrent tasks used. The
    suggested value is equal to the number of CPUs. The concurrent
    tasks are used to execute the <tt>multitask</tt> prerequisites.
    Also see the <tt>-m</tt> option which turns all tasks into
    multitasks.

    Sample values:
     (no -j) : unlimited concurrent tasks (standard rake behavior)
     -j      : 2 concurrent tasks (exact number may change)
     -j 16   : 16 concurrent tasks

[<tt>--job-stats</tt> _level_]

    Display job statistics at the completion of the run. By default,
    this will display the requested number of active tasks (from the
    -j options) and the maximum number of tasks in play at any given
    time.

    If the optional _level_ is <tt>history</tt>, then a complete trace
    of task history will be displayed on standard output.

[<tt>--libdir</tt> _directory_  (-I)]
    Add _directory_ to the list of directories searched for require.

[<tt>--multitask</tt> (-m)]
    Treat all tasks as multitasks. ('make/drake' semantics)

[<tt>--nosearch</tt>  (-N)]
    Do not search for a Rakefile in parent directories.

[<tt>--prereqs</tt>  (-P)]
    Display a list of all tasks and their immediate prerequisites.

[<tt>--quiet</tt> (-q)]
    Do not echo commands from FileUtils.

[<tt>--rakefile</tt> _filename_ (-f)]
    Use _filename_ as the name of the rakefile. The default rakefile
    names are +rakefile+ and +Rakefile+ (with +rakefile+ taking
    precedence). If the rakefile is not found in the current
    directory, +rake+ will search parent directories for a match. The
    directory where the Rakefile is found will become the current
    directory for the actions executed in the Rakefile.

[<tt>--rakelibdir</tt> _rakelibdir_ (-R)]
    Auto-import any .rake files in RAKELIBDIR. (default is 'rakelib')

[<tt>--require</tt> _name_ (-r)]
    Require _name_ before executing the Rakefile.

[<tt>--rules</tt>]
    Trace the rules resolution.

[<tt>--silent (-s)</tt>]
    Like --quiet, but also suppresses the 'in directory' announcement.

[<tt>--suppress-backtrace _pattern_ </tt>]
    Line matching the regular expression _pattern_ will be removed
    from the backtrace output. Note that the --backtrace option is the
    full backtrace without these lines suppressed.

[<tt>--system</tt> (-g)]
    Use the system wide (global) rakefiles. The project Rakefile is
    ignored. By default, the system wide rakefiles are used only if no
    project Rakefile is found. On Unix-like system, the system wide
    rake files are located in $HOME/.rake. On a windows system they
    are stored in $APPDATA/Rake.

[<tt>--no-system</tt> (-G)]
    Use the project level Rakefile, ignoring the system-wide (global)
    rakefiles.

[<tt>--tasks</tt> <em>pattern</em> (-T)]
    Display a list of the major tasks and their comments.  Comments
    are defined using the "desc" command.  If a pattern is given, then
    only tasks matching the pattern are displayed.

[<tt>--trace</tt>{=_output_} (-t)]
    Turn on invoke/execute tracing. Also enable full backtrace on
    errors. The _output_ parameter is optional, but if specified it
    controls where the trace output is sent. If _output_ is
    <tt>stdout</tt>, then trace output is directed to stardard output.
    If _output_ is <tt>stderr</tt>, or if it is missing, then trace
    output is sent to standard error.

[<tt>--verbose</tt> (-v)]
    Echo the Sys commands to standard output.

[<tt>--version</tt> (-V)]
    Display the program version and exit.

[<tt>--where</tt> <em>pattern</em> (-W)]
    Display tasks that match <em>pattern</em> and the file and line
    number where the task is defined. By default this option will
    display all tasks, not just the tasks that have descriptions.

[<tt>--no-deprecation-warnings</tt> (-W)]
    Do not display the deprecation warnings.

In addition, any command line option of the form
<em>VAR</em>=<em>VALUE</em> will be added to the environment hash
<tt>ENV</tt> and may be tested in the Rakefile.
