checkpatch: make -f alias --file, add --help, more verbose help message

my $summary_file = 0;

my $root;

my %debug;

my $help = 0;

sub help {

	my ($exitcode) = @_;

	print << "EOM";

Usage: $P [OPTION]... [FILE]...

Version: $V

Options:

  -q, --quiet                quiet

  --no-tree                  run without a kernel tree

  --no-signoff               do not check for 'Signed-off-by' line

  --patch                    treat FILE as patchfile (default)

  --emacs                    emacs compile window format

  --terse                    one line per report

  -f, --file                 treat FILE as regular source file

  --subjective, --strict     enable more subjective tests

  --root=PATH                PATH to the kernel tree root

  --no-summary               suppress the per-file summary

  --mailback                 only produce a report in case of warnings/errors

  --summary-file             include the filename in summary

  --debug KEY=[0|1]          turn on/off debugging of KEY, where KEY is one of

                             'values', 'possible', 'type', and 'attr' (default

                             is all off)

  --test-only=WORD           report only warnings/errors containing WORD

                             literally

  -h, --help, --version      display this help and exit

When FILE is - read standard input.

EOM

	exit($exitcode);

}

GetOptions(

	'q|quiet+'	=> \$quiet,

	'tree!'		=> \$tree,

	'patch!'	=> \$chk_patch,

	'emacs!'	=> \$emacs,

	'terse!'	=> \$terse,

	'file!'		=> \$file,

	'f|file!'	=> \$file,

	'subjective!'	=> \$check,

	'strict!'	=> \$check,

	'root=s'	=> \$root,

	'debug=s'	=> \%debug,

	'test-only=s'	=> \$tst_only,

) or exit;

	'h|help'	=> \$help,

	'version'	=> \$help

) or help(1);

help(0) if ($help);

my $exit = 0;

if ($#ARGV < 0) {

	print "usage: $P [options] patchfile\n";

	print "version: $V\n";

	print "options: -q               => quiet\n";

	print "         --no-tree        => run without a kernel tree\n";

	print "         --terse          => one line per report\n";

	print "         --emacs          => emacs compile window format\n";

	print "         --file           => check a source file\n";

	print "         --strict         => enable more subjective tests\n";

	print "         --root           => path to the kernel tree root\n";

	print "         --no-summary     => suppress the per-file summary\n";

	print "         --summary-file   => include the filename in summary\n";

	print "$P: no input files\n";

	exit(1);

}