path: root/vest/dist-vest.pl

#!/usr/bin/env perl
use strict;
my @ORIG_ARGV=@ARGV;
use Cwd qw(getcwd);
my $SCRIPT_DIR; BEGIN { use Cwd qw/ abs_path /; use File::Basename; $SCRIPT_DIR = dirname(abs_path($0)); push @INC, $SCRIPT_DIR, "$SCRIPT_DIR/../environment"; }

# Skip local config (used for distributing jobs) if we're running in local-only mode
use LocalConfig;
use Getopt::Long;
use IPC::Open2;
use POSIX ":sys_wait_h";
my $QSUB_CMD = qsub_args(mert_memory());

require "libcall.pl";

# Default settings
my $srcFile;
my $refFiles;
my $bin_dir = $SCRIPT_DIR;
die "Bin directory $bin_dir missing/inaccessible" unless -d $bin_dir;
my $FAST_SCORE="$bin_dir/../mteval/fast_score";
die "Can't execute $FAST_SCORE" unless -x $FAST_SCORE;
my $MAPINPUT = "$bin_dir/mr_vest_generate_mapper_input";
my $MAPPER = "$bin_dir/mr_vest_map";
my $REDUCER = "$bin_dir/mr_vest_reduce";
my $parallelize = "$bin_dir/parallelize.pl";
my $libcall = "$bin_dir/libcall.pl";
my $sentserver = "$bin_dir/sentserver";
my $sentclient = "$bin_dir/sentclient";
my $LocalConfig = "$SCRIPT_DIR/../environment/LocalConfig.pm";

my $SCORER = $FAST_SCORE;
die "Can't find $MAPPER" unless -x $MAPPER;
my $cdec = "$bin_dir/../decoder/cdec";
die "Can't find decoder in $cdec" unless -x $cdec;
die "Can't find $parallelize" unless -x $parallelize;
die "Can't find $libcall" unless -e $libcall;
my $decoder = $cdec;
my $lines_per_mapper = 400;
my $rand_directions = 15;
my $iteration = 1;
my $run_local = 0;
my $best_weights;
my $max_iterations = 15;
my $optimization_iters = 6;
my $decode_nodes = 15;   # number of decode nodes
my $pmem = "9g";
my $disable_clean = 0;
my %seen_weights;
my $normalize;
my $help = 0;
my $epsilon = 0.0001;
my $interval = 5;
my $dryrun = 0;
my $last_score = -10000000;
my $metric = "ibm_bleu";
my $dir;
my $iniFile;
my $weights;
my $initialWeights;
my $decoderOpt;
my $noprimary;
my $maxsim=0;
my $oraclen=0;
my $oracleb=20;
my $bleu_weight=1;
my $use_make;  # use make to parallelize line search
my $dirargs='';
my $density_prune;
my $usefork;
my $pass_suffix = '';
my $cpbin=1;
# Process command-line options
Getopt::Long::Configure("no_auto_abbrev");
if (GetOptions(
	"decoder=s" => \$decoderOpt,
	"decode-nodes=i" => \$decode_nodes,
	"density-prune=f" => \$density_prune,
	"dont-clean" => \$disable_clean,
	"pass-suffix=s" => \$pass_suffix,
        "use-fork" => \$usefork,
	"dry-run" => \$dryrun,
	"epsilon=s" => \$epsilon,
	"help" => \$help,
	"interval" => \$interval,
	"iteration=i" => \$iteration,
	"local" => \$run_local,
	"use-make=i" => \$use_make,
	"max-iterations=i" => \$max_iterations,
	"normalize=s" => \$normalize,
	"pmem=s" => \$pmem,
        "cpbin!" => \$cpbin,
	"rand-directions=i" => \$rand_directions,
	"random_directions=i" => \$rand_directions,
        "bleu_weight=s" => \$bleu_weight,
        "no-primary!" => \$noprimary,
        "max-similarity=s" => \$maxsim,
        "oracle-directions=i" => \$oraclen,
        "n-oracle=i" => \$oraclen,
        "oracle-batch=i" => \$oracleb,
        "directions-args=s" => \$dirargs,
	"ref-files=s" => \$refFiles,
	"metric=s" => \$metric,
	"source-file=s" => \$srcFile,
	"weights=s" => \$initialWeights,
	"workdir=s" => \$dir,
    "opt-iterations=i" => \$optimization_iters,
) == 0 || @ARGV!=1 || $help) {
	print_help();
	exit;
}

if (defined $density_prune) {
  die "--density_prune n: n must be greater than 1.0\n" unless $density_prune > 1.0;
}

if ($usefork) { $usefork = "--use-fork"; } else { $usefork = ''; }

if ($metric =~ /^(combi|ter)$/i) {
  $lines_per_mapper = 40;
}

($iniFile) = @ARGV;


sub write_config;
sub enseg;
sub print_help;

my $nodelist;
my $host =check_output("hostname"); chomp $host;
my $bleu;
my $interval_count = 0;
my $logfile;
my $projected_score;

# used in sorting scores
my $DIR_FLAG = '-r';
if ($metric =~ /^ter$|^aer$/i) {
  $DIR_FLAG = '';
}

my $refs_comma_sep = get_comma_sep_refs('r',$refFiles);

unless ($dir){
	$dir = "vest";
}
unless ($dir =~ /^\//){  # convert relative path to absolute path
	my $basedir = check_output("pwd");
	chomp $basedir;
	$dir = "$basedir/$dir";
}

if ($decoderOpt){ $decoder = $decoderOpt; }


# Initializations and helper functions
srand;

my @childpids = ();
my @cleanupcmds = ();

sub cleanup {
	print STDERR "Cleanup...\n";
	for my $pid (@childpids){ unchecked_call("kill $pid"); }
	for my $cmd (@cleanupcmds){ unchecked_call("$cmd"); }
	exit 1;
};
# Always call cleanup, no matter how we exit
*CORE::GLOBAL::exit = 
    sub{ cleanup(); }; 
$SIG{INT} = "cleanup";
$SIG{TERM} = "cleanup";
$SIG{HUP} = "cleanup";

my $decoderBase = check_output("basename $decoder"); chomp $decoderBase;
my $newIniFile = "$dir/$decoderBase.ini";
my $inputFileName = "$dir/input";
my $user = $ENV{"USER"};


# process ini file
-e $iniFile || die "Error: could not open $iniFile for reading\n";
open(INI, $iniFile);

use File::Basename qw(basename);
#pass bindir, refs to vars holding bin
sub modbin {
    local $_;
    my $bindir=shift;
    check_call("mkdir -p $bindir");
    -d $bindir || die "couldn't make bindir $bindir";
    for (@_) {
        my $src=$$_;
        $$_="$bindir/".basename($src);
        check_call("cp -p $src $$_");
    }
}
sub dirsize {
    opendir ISEMPTY,$_[0];
    return scalar(readdir(ISEMPTY))-1;
}
if ($dryrun){
	write_config(*STDERR);
	exit 0;
} else {
	if (-e $dir && dirsize($dir)>1 && -e "$dir/hgs" ){ # allow preexisting logfile, binaries, but not dist-vest.pl outputs
	  die "ERROR: working dir $dir already exists\n\n";
	} else {
		-e $dir || mkdir $dir;
		mkdir "$dir/hgs";
        modbin("$dir/bin",\$LocalConfig,\$cdec,\$SCORER,\$MAPINPUT,\$MAPPER,\$REDUCER,\$parallelize,\$sentserver,\$sentclient,\$libcall) if $cpbin;
    mkdir "$dir/scripts";
        my $cmdfile="$dir/rerun-vest.sh";
        open CMD,'>',$cmdfile;
        print CMD "cd ",&getcwd,"\n";
#        print CMD &escaped_cmdline,"\n"; #buggy - last arg is quoted.
        my $cline=&cmdline."\n";
        print CMD $cline;
        close CMD;
        print STDERR $cline;
        chmod(0755,$cmdfile);
		unless (-e $initialWeights) {
			print STDERR "Please specify an initial weights file with --initial-weights\n";
			print_help();
			exit;
		}
		check_call("cp $initialWeights $dir/weights.0");
		die "Can't find weights.0" unless (-e "$dir/weights.0");
	}
	write_config(*STDERR);
}


# Generate initial files and values
check_call("cp $iniFile $newIniFile");
$iniFile = $newIniFile;

my $newsrc = "$dir/dev.input";
enseg($srcFile, $newsrc);
$srcFile = $newsrc;
my $devSize = 0;
open F, "<$srcFile" or die "Can't read $srcFile: $!";
while(<F>) { $devSize++; }
close F;

unless($best_weights){ $best_weights = $weights; }
unless($projected_score){ $projected_score = 0.0; }
$seen_weights{$weights} = 1;

my $random_seed = int(time / 1000);
my $lastWeightsFile;
my $lastPScore = 0;
# main optimization loop
while (1){
	print STDERR "\n\nITERATION $iteration\n==========\n";

	if ($iteration > $max_iterations){
		print STDERR "\nREACHED STOPPING CRITERION: Maximum iterations\n";
		last;
	}
	# iteration-specific files
	my $runFile="$dir/run.raw.$iteration";
	my $onebestFile="$dir/1best.$iteration";
	my $logdir="$dir/logs.$iteration";
	my $decoderLog="$logdir/decoder.sentserver.log.$iteration";
	my $scorerLog="$logdir/scorer.log.$iteration";
	check_call("mkdir -p $logdir");


	#decode
	print STDERR "RUNNING DECODER AT ";
	print STDERR unchecked_output("date");
	my $im1 = $iteration - 1;
	my $weightsFile="$dir/weights.$im1";
	my $decoder_cmd = "$decoder -c $iniFile --weights$pass_suffix $weightsFile -O $dir/hgs";
	if ($density_prune) {
		$decoder_cmd .= " --density_prune $density_prune";
	}
	my $pcmd;
	if ($run_local) {
		$pcmd = "cat $srcFile |";
	} elsif ($use_make) {
	    # TODO: Throw error when decode_nodes is specified along with use_make
		$pcmd = "cat $srcFile | $parallelize --use-fork -p $pmem -e $logdir -j $use_make --";
	} else {
		$pcmd = "cat $srcFile | $parallelize $usefork -p $pmem -e $logdir -j $decode_nodes --";
	}
	my $cmd = "$pcmd $decoder_cmd 2> $decoderLog 1> $runFile";
	print STDERR "COMMAND:\n$cmd\n";
	check_bash_call($cmd);
        my $num_hgs = check_output("ls $dir/hgs/*.gz | wc -l");
        print STDERR "NUMBER OF HGs: $num_hgs\n";
	die "Dev set contains $devSize sentences! Decoder failure?\n" if ($devSize != $num_hgs);
	my $dec_score = check_output("cat $runFile | $SCORER $refs_comma_sep -l $metric");
	chomp $dec_score;
	print STDERR "DECODER SCORE: $dec_score\n";

	# save space
	check_call("gzip -f $runFile");
	check_call("gzip -f $decoderLog");

	# run optimizer
	print STDERR "RUNNING OPTIMIZER AT ";
	print STDERR unchecked_output("date");
	my $mergeLog="$logdir/prune-merge.log.$iteration";

	my $score = 0;
	my $icc = 0;
	my $inweights="$dir/weights.$im1";
	for (my $opt_iter=1; $opt_iter<$optimization_iters; $opt_iter++) {
		print STDERR "\nGENERATE OPTIMIZATION STRATEGY (OPT-ITERATION $opt_iter/$optimization_iters)\n";
		print STDERR unchecked_output("date");
		$icc++;
		my $nop=$noprimary?"--no_primary":"";
		my $targs=$oraclen ? "--decoder_translations='$runFile.gz' ".get_comma_sep_refs('-references',$refFiles):"";
		my $bwargs=$bleu_weight!=1 ? "--bleu_weight=$bleu_weight":"";
		$cmd="$MAPINPUT -w $inweights -r $dir/hgs $bwargs -s $devSize -d $rand_directions --max_similarity=$maxsim --oracle_directions=$oraclen --oracle_batch=$oracleb $targs $dirargs > $dir/agenda.$im1-$opt_iter";
		print STDERR "COMMAND:\n$cmd\n";
		check_call($cmd);
		check_call("mkdir -p $dir/splag.$im1");
		$cmd="split -a 3 -l $lines_per_mapper $dir/agenda.$im1-$opt_iter $dir/splag.$im1/mapinput.";
		print STDERR "COMMAND:\n$cmd\n";
		check_call($cmd);
		opendir(DIR, "$dir/splag.$im1") or die "Can't open directory: $!";
		my @shards = grep { /^mapinput\./ } readdir(DIR);
		closedir DIR;
		die "No shards!" unless scalar @shards > 0;
		my $joblist = "";
		my $nmappers = 0;
		my @mapoutputs = ();
		@cleanupcmds = ();
		my %o2i = ();
		my $first_shard = 1;
		my $mkfile; # only used with makefiles
		my $mkfilename;
		if ($use_make) {
			$mkfilename = "$dir/splag.$im1/domap.mk";
			open $mkfile, ">$mkfilename" or die "Couldn't write $mkfilename: $!";
			print $mkfile "all: $dir/splag.$im1/map.done\n\n";
		}
		my @mkouts = ();  # only used with makefiles
		for my $shard (@shards) {
			my $mapoutput = $shard;
			my $client_name = $shard;
			$client_name =~ s/mapinput.//;
			$client_name = "vest.$client_name";
			$mapoutput =~ s/mapinput/mapoutput/;
			push @mapoutputs, "$dir/splag.$im1/$mapoutput";
			$o2i{"$dir/splag.$im1/$mapoutput"} = "$dir/splag.$im1/$shard";
			my $script = "$MAPPER -s $srcFile -l $metric $refs_comma_sep < $dir/splag.$im1/$shard | sort -t \$'\\t' -k 1 > $dir/splag.$im1/$mapoutput";
			if ($run_local) {
				print STDERR "COMMAND:\n$script\n";
				check_bash_call($script);
			} elsif ($use_make) {
				my $script_file = "$dir/scripts/map.$shard";
				open F, ">$script_file" or die "Can't write $script_file: $!";
				print F "#!/bin/bash\n";
				print F "$script\n";
				close F;
				my $output = "$dir/splag.$im1/$mapoutput";
				push @mkouts, $output;
				chmod(0755, $script_file) or die "Can't chmod $script_file: $!";
				if ($first_shard) { print STDERR "$script\n"; $first_shard=0; }
				print $mkfile "$output: $dir/splag.$im1/$shard\n\t$script_file\n\n";
			} else {
				my $script_file = "$dir/scripts/map.$shard";
				open F, ">$script_file" or die "Can't write $script_file: $!";
				print F "$script\n";
				close F;
				if ($first_shard) { print STDERR "$script\n"; $first_shard=0; }

				$nmappers++;
				my $qcmd = "$QSUB_CMD -N $client_name -o /dev/null -e $logdir/$client_name.ER $script_file";
				my $jobid = check_output("$qcmd");
				chomp $jobid;
				$jobid =~ s/^(\d+)(.*?)$/\1/g;
				$jobid =~ s/^Your job (\d+) .*$/\1/;
		 	 	push(@cleanupcmds, "qdel $jobid 2> /dev/null");
				print STDERR " $jobid";
				if ($joblist == "") { $joblist = $jobid; }
				else {$joblist = $joblist . "\|" . $jobid; }
			}
		}
		if ($run_local) {
			print STDERR "\nProcessing line search complete.\n";
		} elsif ($use_make) {
			print $mkfile "$dir/splag.$im1/map.done: @mkouts\n\ttouch $dir/splag.$im1/map.done\n\n";
			close $mkfile;
			my $mcmd = "make -j $use_make -f $mkfilename";
			print STDERR "\nExecuting: $mcmd\n";
			check_call($mcmd);
		} else {
			print STDERR "\nLaunched $nmappers mappers.\n";
      			sleep 8;
			print STDERR "Waiting for mappers to complete...\n";
			while ($nmappers > 0) {
			  sleep 5;
			  my @livejobs = grep(/$joblist/, split(/\n/, check_output("qstat | grep -v ' C '")));
			  $nmappers = scalar @livejobs;
			}
			print STDERR "All mappers complete.\n";
		}
		my $tol = 0;
		my $til = 0;
		for my $mo (@mapoutputs) {
		  my $olines = get_lines($mo);
		  my $ilines = get_lines($o2i{$mo});
		  $tol += $olines;
		  $til += $ilines;
		  die "$mo: output lines ($olines) doesn't match input lines ($ilines)" unless $olines==$ilines;
		}
		print STDERR "Results for $tol/$til lines\n";
		print STDERR "\nSORTING AND RUNNING VEST REDUCER\n";
		print STDERR unchecked_output("date");
		$cmd="sort -t \$'\\t' -k 1 @mapoutputs | $REDUCER -l $metric > $dir/redoutput.$im1";
		print STDERR "COMMAND:\n$cmd\n";
		check_bash_call($cmd);
		$cmd="sort -nk3 $DIR_FLAG '-t|' $dir/redoutput.$im1 | head -1";
		my $best=check_bash_output("$cmd"); chomp $best;
		print STDERR "$best\n";
		my ($oa, $x, $xscore) = split /\|/, $best;
		$score = $xscore;
		print STDERR "PROJECTED SCORE: $score\n";
		if (abs($x) < $epsilon) {
			print STDERR "\nOPTIMIZER: no score improvement: abs($x) < $epsilon\n";
			last;
		}
                my $psd = $score - $last_score;
                $last_score = $score;
		if (abs($psd) < $epsilon) {
			print STDERR "\nOPTIMIZER: no score improvement: abs($psd) < $epsilon\n";
			last;
		}
		my ($origin, $axis) = split /\s+/, $oa;

		my %ori = convert($origin);
		my %axi = convert($axis);

		my $finalFile="$dir/weights.$im1-$opt_iter";
		open W, ">$finalFile" or die "Can't write: $finalFile: $!";
                my $norm = 0;
		for my $k (sort keys %ori) {
			my $dd = $ori{$k} + $axi{$k} * $x;
                        $norm += $dd * $dd;
		}
                $norm = sqrt($norm);
		$norm = 1;
		for my $k (sort keys %ori) {
			my $v = ($ori{$k} + $axi{$k} * $x) / $norm;
			print W "$k $v\n";
		}
		check_call("rm -rf $dir/splag.$im1");
		$inweights = $finalFile;
	}
	$lastWeightsFile = "$dir/weights.$iteration";
	check_call("cp $inweights $lastWeightsFile");
	if ($icc < 2) {
		print STDERR "\nREACHED STOPPING CRITERION: score change too little\n";
		last;
	}
	$lastPScore = $score;
	$iteration++;
	print STDERR "\n==========\n";
}

print STDERR "\nFINAL WEIGHTS: $lastWeightsFile\n(Use -w <this file> with the decoder)\n\n";

print STDOUT "$lastWeightsFile\n";

exit 0;

sub normalize_weights {
  my ($rfn, $rpts, $feat) = @_;
  my @feat_names = @$rfn;
  my @pts = @$rpts;
  my $z = 1.0;
  for (my $i=0; $i < scalar @feat_names; $i++) {
    if ($feat_names[$i] eq $feat) {
      $z = $pts[$i];
      last;
    }
  }
  for (my $i=0; $i < scalar @feat_names; $i++) {
    $pts[$i] /= $z;
  }
  print STDERR " NORM WEIGHTS: @pts\n";
  return @pts;
}

sub get_lines {
  my $fn = shift @_;
  open FL, "<$fn" or die "Couldn't read $fn: $!";
  my $lc = 0;
  while(<FL>) { $lc++; }
  return $lc;
}

sub get_comma_sep_refs {
  my ($r,$p) = @_;
  my $o = check_output("echo $p");
  chomp $o;
  my @files = split /\s+/, $o;
  return "-$r " . join(" -$r ", @files);
}

sub read_weights_file {
  my ($file) = @_;
  open F, "<$file" or die "Couldn't read $file: $!";
  my @r = ();
  my $pm = -1;
  while(<F>) {
    next if /^#/;
    next if /^\s*$/;
    chomp;
    if (/^(.+)\s+(.+)$/) {
      my $m = $1;
      my $w = $2;
      die "Weights out of order: $m <= $pm" unless $m > $pm;
      push @r, $w;
    } else {
      warn "Unexpected feature name in weight file: $_";
    }
  }
  close F;
  return join ' ', @r;
}

# subs
sub write_config {
	my $fh = shift;
	my $cleanup = "yes";
	if ($disable_clean) {$cleanup = "no";}

	print $fh "\n";
	print $fh "DECODER:          $decoder\n";
	print $fh "INI FILE:         $iniFile\n";
	print $fh "WORKING DIR:      $dir\n";
	print $fh "SOURCE (DEV):     $srcFile\n";
	print $fh "REFS (DEV):       $refFiles\n";
	print $fh "EVAL METRIC:      $metric\n";
	print $fh "START ITERATION:  $iteration\n";
	print $fh "MAX ITERATIONS:   $max_iterations\n";
	print $fh "DECODE NODES:     $decode_nodes\n";
	print $fh "HEAD NODE:        $host\n";
	print $fh "PMEM (DECODING):  $pmem\n";
	print $fh "CLEANUP:          $cleanup\n";
	print $fh "INITIAL WEIGHTS:  $initialWeights\n";
}

sub update_weights_file {
  my ($neww, $rfn, $rpts) = @_;
  my @feats = @$rfn;
  my @pts = @$rpts;
  my $num_feats = scalar @feats;
  my $num_pts = scalar @pts;
  die "$num_feats (num_feats) != $num_pts (num_pts)" unless $num_feats == $num_pts;
  open G, ">$neww" or die;
  for (my $i = 0; $i < $num_feats; $i++) {
    my $f = $feats[$i];
    my $lambda = $pts[$i];
    print G "$f $lambda\n";
  }
  close G;
}

sub enseg {
	my $src = shift;
	my $newsrc = shift;
	open(SRC, $src);
	open(NEWSRC, ">$newsrc");
	my $i=0;
	while (my $line=<SRC>){
		chomp $line;
		if ($line =~ /^\s*<seg/i) {
			print NEWSRC "$line\n";
		} else {
			print NEWSRC "<seg id=\"$i\">$line</seg>\n";
		}
		$i++;
	}
	close SRC;
	close NEWSRC;
}

sub print_help {

	my $executable = check_output("basename $0"); chomp $executable;
    print << "Help";

Usage: $executable [options] <ini file>

	$executable [options] <ini file>
		Runs a complete MERT optimization and test set decoding, using
		the decoder configuration in ini file.  Note that many of the
		options have default values that are inferred automatically
		based on certain conventions.  For details, refer to descriptions
		of the options --decoder, --weights, and --workdir.

Options:

	--local
		Run the decoder and optimizer locally with a single thread.

	--use-make <I>
		Use make -j <I> to run the optimizer commands (useful on large
		shared-memory machines where qsub is unavailable).

	--decode-nodes <I>
		Number of decoder processes to run in parallel. [default=15]

	--decoder <decoder path>
		Decoder binary to use.

	--density-prune <N>
		Limit the density of the hypergraph on each iteration to N times
		the number of edges on the Viterbi path.

	--help
		Print this message and exit.

	--iteration <I>
		Starting iteration number.  If not specified, defaults to 1.

	--max-iterations <M>
		Maximum number of iterations to run.  If not specified, defaults
		to 10.

	--pass-suffix <S>
		If the decoder is doing multi-pass decoding, the pass suffix "2",
		"3", etc., is used to control what iteration of weights is set.

	--pmem <N>
		Amount of physical memory requested for parallel decoding jobs.

	--ref-files <files>
		Dev set ref files.  This option takes only a single string argument.
		To use multiple files (including file globbing), this argument should
		be quoted.

	--metric <method>
		Metric to optimize.
		Example values: IBM_BLEU, NIST_BLEU, Koehn_BLEU, TER, Combi

	--normalize <feature-name>
		After each iteration, rescale all feature weights such that feature-
		name has a weight of 1.0.

	--rand-directions <num>
		MERT will attempt to optimize along all of the principle directions,
		set this parameter to explore other directions. Defaults to 5.

	--source-file <file>
		Dev set source file.

	--weights <file>
		A file specifying initial feature weights.  The format is
		FeatureName_1 value1
		FeatureName_2 value2

	--workdir <dir>
		Directory for intermediate and output files.  If not specified, the
		name is derived from the ini filename.  Assuming that the ini
		filename begins with the decoder name and ends with ini, the default
		name of the working directory is inferred from the middle part of
		the filename.  E.g. an ini file named decoder.foo.ini would have
		a default working directory name foo.

Help
}

sub convert {
  my ($str) = @_;
  my @ps = split /;/, $str;
  my %dict = ();
  for my $p (@ps) {
    my ($k, $v) = split /=/, $p;
    $dict{$k} = $v;
  }
  return %dict;
}



sub cmdline {
    return join ' ',($0,@ORIG_ARGV);
}

#buggy: last arg gets quoted sometimes?
my $is_shell_special=qr{[ \t\n\\><|&;"'`~*?{}$!()]};
my $shell_escape_in_quote=qr{[\\"\$`!]};

sub escape_shell {
    my ($arg)=@_;
    return undef unless defined $arg;
    if ($arg =~ /$is_shell_special/) {
        $arg =~ s/($shell_escape_in_quote)/\\$1/g;
        return "\"$arg\"";
    }
    return $arg;
}

sub escaped_shell_args {
    return map {local $_=$_;chomp;escape_shell($_)} @_;
}

sub escaped_shell_args_str {
    return join ' ',&escaped_shell_args(@_);
}

sub escaped_cmdline {
    return "$0 ".&escaped_shell_args_str(@ORIG_ARGV);
}