cat_max

来自「EM算法的改进」· 代码 · 共 86 行

#!/usr/bin/perl
#
# $Id: cat_max.txt 1339 2006-09-21 19:46:28Z tbailey $
# $Log$
# Revision 1.1  2005/07/28 23:51:55  nadya
# Initial revision
#
#
# AUTHOR: Timothy L. Bailey
# CREATE DATE:

$PGM = $0;			# name of program
$PGM =~ s#.*/##;                # remove part up to last slash
@args = @ARGV;			# arguments to program
$| = 1;				# flush after all prints
$SIG{'INT'} = 'cleanup';	# interrupt handler
# Note: so that interrupts work, always use for system calls:
# 	if ($status = system($command)) {&cleanup($status)}

# requires
push(@INC, split(":", $ENV{'PATH'}));	# look in entire path

# defaults
$bufsize = 65536;

$usage = <<USAGE;		# usage message
  USAGE:
	$PGM <max>

	Reads standard input.
	Writes standard output.

	Copies standard input to standard output and quits with $status 1
	if more than <max> bytes are written.
        Copyright
        (2000) The Regents of the University of California.
        All Rights Reserved.
        Author: Timothy L. Bailey
USAGE

$nargs = 1;			# number of required args
if ($#ARGV+1 < $nargs) { &print_usage("$usage", 1); }

# get input arguments
while ($#ARGV >= 0) {
  $_ = shift;
  if ($_ eq "-h") {				# help
    &print_usage("$usage", 0);
  } else {
    $max = $_;
  }
}

$tot = 0;
while ($n = read(STDIN, $_, $bufsize)) {
  $tot += $n;
  exit(1) if ($tot > $max);
  print STDOUT;
}
exit(0);

################################################################################
#                       Subroutines                                            #
################################################################################
 
################################################################################
#
#       print_usage
#
#	Print the usage message and exit.
#
################################################################################
sub print_usage {
  my($usage, $status) = @_;
 
  if (-c STDOUT) {			# standard output is a terminal
    open(C, "| more");
    print C $usage;
    close C;
  } else {				# standard output not a terminal
    print STDERR $usage;
  }

  exit $status;
}