Perl script

[Jame Brooke]

#!/usr/bin/perl
 
$type = "u";
 
if ( $ARGV[0] =~ /^-([udm])$/ ) {
    $type = $1;
    shift @ARGV;
}
&convert(@ARGV);
 
sub convert {
   my(@files) [EMAIL PROTECTED];
 
 
 
   foreach my $file (@files) {
       next if (not -T $file );
       print "Converting file: $file\n";
       unless (open(IN, "<$file") ) {
          print qq|Unable to open file "$file"\n|;
          next;
}
      unless ( open(OUT, ">${file}.tmp") ) {
         print qq|Unable to open temporary output file\n|;
         next;
}
 
     if ( $type eq 'u' ) { 
        while (<IN>) { s/\r\n/\n/g; print OUT; }
     } elsif ( $type eq 'm' ) {        
        while (<IN>) { s/\r\n|\n/g; print OUT; }
     } elsif ( $type eq 'd' ) {
        while (<IN>) { s/\r|\n/\r\n/g; print OUT; }
}
  close OUT;
  close IN;
 
unless ( rename("file", "${file}~") ) {
    print qq|Failed to rename old file\n|;
    next;
}
unless ( rename("${file}.tmp", "$file") ) {
    print qq|Failed to rename new file\n|;
    next;
}
}
}
 
I have few question regarding code above, 
 
1. what the function for     
   
if ( $ARGV[0] =~ /^-([udm])$/ ) {
    $type = $1;
    shift @ARGV;
}
&convert(@ARGV);
 
2. How i add line to the script that would print out a usage line, if wrong number of 
the argument are give in the script?
 
thanks, any comment. 





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