+sub startingconfig {
+       %alias=%config=%configfiles=%knownactions=%loaded=();
+       my $datapos=tell(DATA);
+       loadconfig(\*DATA);
+       seek(DATA,$datapos,0); # rewind
+}
+
+sub modifyconfig {
+       my $f=shift;
+       # the section to modify or add
+       my $targetsection=shift;
+       # fields to change in the section
+       # To remove a field, set its value to "".
+       my %changefields=@_;
+
+       my @lines;
+       my @out;
+
+       if (-e $f) {
+               open(my $in, "<", $f) || die "mr: open $f: $!\n";
+               @lines=<$in>;
+               close $in;
+       }
+
+       my $formatfield=sub {
+               my $field=shift;
+               my @value=split(/\n/, shift);
+
+               return "$field = ".shift(@value)."\n".
+                       join("", map { "\t$_\n" } @value);
+       };
+       my $addfields=sub {
+               my @blanks;
+               while ($out[$#out] =~ /^\s*$/) {
+                       unshift @blanks, pop @out;
+               }
+               foreach my $field (sort keys %changefields) {
+                       if (length $changefields{$field}) {
+                               push @out, "$field = $changefields{$field}\n";
+                               delete $changefields{$field};
+                       }
+               }
+               push @out, @blanks;
+       };
+
+       my $section;
+       while (@lines) {
+               $_=shift(@lines);
+
+               if (/^\s*\#/ || /^\s*$/) {
+                       push @out, $_;
+               }
+               elsif (/^\[([^\]]*)\]\s*$/) {
+                       if (defined $section && 
+                           $section eq $targetsection) {
+                               $addfields->();
+                       }
+
+                       $section=expandenv($1);
+
+                       push @out, $_;
+               }
+               elsif (/^(\w+)\s*=\s(.*)/) {
+                       my $parameter=$1;
+                       my $value=$2;
+
+                       # continued value
+                       while (@lines && $lines[0]=~/^\s(.+)/) {
+                               shift(@lines);
+                               $value.="\n$1";
+                               chomp $value;
+                       }
+
+                       if ($section eq $targetsection) {
+                               if (exists $changefields{$parameter}) {
+                                       if (length $changefields{$parameter}) {
+                                               $value=$changefields{$parameter};
+                                       }
+                                       delete $changefields{$parameter};
+                               }
+                       }
+
+                       push @out, $formatfield->($parameter, $value);
+               }
+       }
+
+       if (defined $section && 
+           $section eq $targetsection) {
+               $addfields->();
+       }
+       elsif (%changefields) {
+               push @out, "\n[$targetsection]\n";
+               foreach my $field (sort keys %changefields) {
+                       if (length $changefields{$field}) {
+                               push @out, $formatfield->($field, $changefields{$field});
+                       }
+               }
+       }
+
+       open(my $out, ">", $f) || die "mr: write $f: $!\n";
+       print $out @out;
+       close $out;     
+}
+
+sub dispatch {
+       my $action=shift;
+
+       # actions that do not operate on all repos
+       if ($action eq 'config') {
+               config(@ARGV);
+       }
+       elsif ($action eq 'register') {
+               register(@ARGV);
+       }
+       elsif ($action eq 'bootstrap') {
+               bootstrap();
+       }
+       elsif ($action eq 'remember' ||
+              $action eq 'offline' ||
+              $action eq 'online') {
+               my @repos=selectrepos;
+               action($action, @{$repos[0]}) if @repos;
+               exit 0;
+       }
+
+       if (!$jobs || $jobs > 1) {
+               mrs($action, selectrepos());
+       }
+       else {
+               foreach my $repo (selectrepos()) {
+                       record($repo, action($action, @$repo));
+               }
+       }
+}
+
+sub help {
+       my $help=q#
+               case `uname -s` in
+                       SunOS)
+                       SHOWMANFILE="man -f"
+                       ;;
+                       Darwin)
+                       SHOWMANFILE="man"
+                       ;;
+                       *)
+                       SHOWMANFILE="man"
+                       ;;
+               esac
+               if [ ! -e "$MR_PATH" ]; then
+                       error "cannot find program path"
+               fi
+               tmp=$(mktemp -t mr.XXXXXXXXXX) || error "mktemp failed"
+               trap "rm -f $tmp" exit
+               pod2man -c mr "$MR_PATH" > "$tmp" || error "pod2man failed"
+               $SHOWMANFILE "$tmp" || error "man failed"
+       #;
+       exec($help) || die "exec: $!";
+}
+
+sub config {
+       if (@_ < 2) {
+               die "mr config: not enough parameters\n";
+       }
+       my $section=shift;
+       if ($section=~/^\//) {
+               # try to convert to a path relative to the config file
+               my ($dir)=$ENV{MR_CONFIG}=~/^(.*\/)[^\/]+$/;
+               $dir=abs_path($dir);
+               $dir.="/" unless $dir=~/\/$/;
+               if ($section=~/^\Q$dir\E(.*)/) {
+                       $section=$1;
+               }
+       }
+       my %changefields;
+       foreach (@_) {
+               if (/^([^=]+)=(.*)$/) {
+                       $changefields{$1}=$2;
+               }
+               else {
+                       my $found=0;
+                       foreach my $topdir (sort keys %config) {
+                               if (exists $config{$topdir}{$section} &&
+                                   exists $config{$topdir}{$section}{$_}) {
+                                       print $config{$topdir}{$section}{$_}."\n";
+                                       $found=1;
+                                       last if $section eq 'DEFAULT';
+                               }
+                       }
+                       if (! $found) {
+                               die "mr config: $section $_ not set\n";
+                       }
+               }
+       }
+       modifyconfig($ENV{MR_CONFIG}, $section, %changefields) if %changefields;
+       exit 0;
+}
+
+sub register {
+       if ($config_overridden) {
+               # Find the directory that the specified config file is
+               # located in.
+               ($directory)=abs_path($ENV{MR_CONFIG})=~/^(.*\/)[^\/]+$/;
+       }
+       else {
+               # Find the closest known mrconfig file to the current
+               # directory.
+               $directory.="/" unless $directory=~/\/$/;
+               my $foundconfig=0;
+               foreach my $topdir (reverse sort keys %config) {
+                       next unless length $topdir;
+                       if ($directory=~/^\Q$topdir\E/) {
+                               $ENV{MR_CONFIG}=$configfiles{$topdir};
+                               $directory=$topdir;
+                               $foundconfig=1;
+                               last;
+                       }
+               }
+               if (! $foundconfig) {
+                       $directory=""; # no config file, use builtin
+               }
+       }
+       if (@ARGV) {
+               my $subdir=shift @ARGV;
+               if (! chdir($subdir)) {
+                       print STDERR "mr register: failed to chdir to $subdir: $!\n";
+               }
+       }
+
+       $ENV{MR_REPO}=getcwd();
+       my $command=findcommand("register", $ENV{MR_REPO}, $directory, 'DEFAULT', 0);
+       if (! defined $command) {
+               die "mr register: unknown repository type\n";
+       }
+
+       $ENV{MR_REPO}=~s/.*\/(.*)/$1/;
+       $command="set -e; ".$config{$directory}{DEFAULT}{lib}."\n".
+               "my_action(){ $command\n }; my_action ".
+               join(" ", map { s/\\/\\\\/g; s/"/\"/g; '"'.$_.'"' } @ARGV);
+       print "mr register: running >>$command<<\n" if $verbose;
+       exec($command) || die "exec: $!";
+}
+
+sub bootstrap {
+       eval q{use File::Copy};
+       die $@ if $@;
+
+       my $src=shift @ARGV;
+       my $dir=shift @ARGV || ".";
+       
+       if (! defined $src || ! length $src) {
+               die "mr: bootstrap requires source\n";
+       }
+
+       # Retrieve config file.
+       eval q{use File::Temp};
+       die $@ if $@;
+       my $tmpconfig=File::Temp->new();
+       if ($src =~ m!^[\w\d]+://!) {
+               # Download the config file to a temporary location.
+               my @downloader;
+               if ($src =~ m!^ssh://(.*)!) {
+                       @downloader = ("scp", $1, $tmpconfig);
+               }
+               else {
+                       @downloader = ("curl", "-A", "mr", "-L", "-s", $src, "-o", $tmpconfig);
+                       push(@downloader, "-k") if $insecure;
+               }
+               my $status = system(@downloader);
+               die "mr bootstrap: invalid SSL certificate for $src (consider -k)\n"
+                       if $downloader[0] eq 'curl' && $status >> 8 == 60;
+               die "mr bootstrap: download of $src failed\n" if $status != 0;
+       }
+       elsif ($src eq '-') {
+               # Config file is read from stdin.
+               copy(\*STDIN, $tmpconfig) || die "stdin: $!";
+       }
+       else {
+               # Config file is local.
+               die "mr bootstrap: cannot read file '$src'"
+                       unless -r $src;
+               copy($src, $tmpconfig) || die "copy: $!";
+       }
+
+       # Sanity check on destination directory.
+       if (! -e $dir) {
+               system("mkdir", "-p", $dir);
+       }
+       chdir($dir) || die "chdir $dir: $!";
+
+       # Special case to handle checkout of the "." repo, which 
+       # would normally be skipped.
+       my $topdir=abs_path(".")."/";
+       my @repo=($topdir, $topdir, ".");
+       loadconfig($tmpconfig, $topdir, $src);
+       record(\@repo, action("checkout", @repo, 1))
+               if exists $config{$topdir}{"."}{"checkout"};
+
+       if (-e ".mrconfig") {
+               print STDERR "mr bootstrap: .mrconfig file already exists, not overwriting with $src\n";
+       }
+       else {
+               move($tmpconfig, ".mrconfig") || die "rename: $!";
+       }
+
+       # Reload the config file (in case we got a different version)
+       # and checkout everything else.
+       startingconfig();
+       loadconfig(".mrconfig");
+       dispatch("checkout");
+       @skipped=grep { abs_path($_) ne abs_path($topdir) } @skipped;
+       showstats("bootstrap");
+       exitstats();
+}
+
+# alias expansion and command stemming
+sub expandaction {
+       my $action=shift;
+       if (exists $alias{$action}) {
+               $action=$alias{$action};
+       }
+       if (! exists $knownactions{$action}) {
+               my @matches = grep { /^\Q$action\E/ }
+                       keys %knownactions, keys %alias;
+               if (@matches == 1) {
+                       $action=$matches[0];
+               }
+               elsif (@matches == 0) {
+                       die "mr: unknown action \"$action\" (known actions: ".
+                               join(", ", sort keys %knownactions).")\n";
+               }
+               else {
+                       die "mr: ambiguous action \"$action\" (matches: ".
+                               join(", ", @matches).")\n";
+               }
+       }
+       return $action;
+}
+
+sub find_mrconfig {
+       my $dir=getcwd();
+       while (length $dir) {
+               if (-e "$dir/.mrconfig") {
+                       return "$dir/.mrconfig";
+               }
+               $dir=~s/\/[^\/]*$//;
+       }
+       return $HOME_MR_CONFIG;
+}
+
+sub getopts {
+       my @saved=@ARGV;
+       Getopt::Long::Configure("bundling", "no_permute");
+       my $result=GetOptions(
+               "d|directory=s" => sub { $directory=abs_path($_[1]) },
+               "c|config=s" => sub { $ENV{MR_CONFIG}=$_[1]; $config_overridden=1 },
+               "p|path" => sub { }, # now default, ignore
+               "f|force" => \$force,
+               "v|verbose" => \$verbose,
+               "m|minimal" => \$minimal,
+               "q|quiet" => \$quiet,
+               "s|stats" => \$stats,
+               "k|insecure" => \$insecure,
+               "i|interactive" => \$interactive,
+               "n|no-recurse:i" => \$max_depth,
+               "j|jobs:i" => \$jobs,
+               "t|trust-all" => \$trust_all,
+       );
+       if (! $result || @ARGV < 1) {
+               die("Usage: mr [options] action [params ...]\n".
+                   "(Use mr help for man page.)\n");
+       }
+       
+       $ENV{MR_SWITCHES}="";
+       foreach my $option (@saved) {
+               last if $option eq $ARGV[0];
+               $ENV{MR_SWITCHES}.="$option ";
+       }
+}
+
+sub check {
+       my @env = qw(GIT_DIR GIT_INDEX_FILE GIT_OBJECT_DIRECTORY GIT_WORK_TREE VCSH_COMMAND VCSH_DIRECTORY VCSH_REPO_NAME);
+       foreach (@env) {
+               die ("mr: environment variable '$_' is set. You are about to shoot your own foot.\n") if ($ENV{$_});
+       }
+}
+
+sub init {
+       $SIG{INT}=sub {
+               print STDERR "mr: interrupted\n";
+               exit 2;
+       };
+       
+       # This can happen if it's run in a directory that was removed
+       # or other strangeness.
+       if (! defined $directory) {
+               die("mr: failed to determine working directory\n");
+       }
+       # Make sure MR_CONFIG is an absolute path, but don't use abs_path since
+       # the config file might be a symlink to elsewhere, and the directory it's
+       # in is significant.
+       if ($ENV{MR_CONFIG} !~ /^\//) {
+               $ENV{MR_CONFIG}=getcwd()."/".$ENV{MR_CONFIG};
+       }
+       # Try to set MR_PATH to the path to the program.
+       eval {
+               use FindBin qw($Bin $Script);
+               $ENV{MR_PATH}=$Bin."/".$Script;
+       };
+}
+       
+sub exitstats {
+       if (@failed) {
+               exit 1;
+       }
+       else {
+               exit 0;
+       }
+}
+
+sub main {
+       getopts();
+       check();
+       init();
+       help(@ARGV) if $ARGV[0] eq 'help';
+
+       startingconfig();
+       loadconfig($HOME_MR_CONFIG);
+       loadconfig($ENV{MR_CONFIG});
+       #use Data::Dumper; print Dumper(\%config);
+       
+       my $action=expandaction(shift @ARGV);
+       dispatch($action);
+
+       showstats($action);
+       exitstats();
+}
+