uudecode: implement -i option

bin/uudecode

@@ -16,16 +16,17 @@ License: perl
 
 use strict;
 
-END {
-    close STDOUT            or die "$0: can't close stdout: $!\n";
-    $? = 1 if $? == 255;    # from die
-}
+use File::Basename qw(basename);
+use Getopt::Std qw(getopts);
 
-my $output_file;
-if( $ARGV[0] eq '-o' ) {
-	shift @ARGV;
-	$output_file = shift @ARGV;
-	}
+use constant EX_SUCCESS => 0;
+use constant EX_FAILURE => 1;
+
+my $Program = basename($0);
+
+my %opt;
+getopts('io:', \%opt) or usage();
+my $output_file = $opt{'o'};
 
 FILESPEC :
 while (<>) {
@@ -34,14 +35,26 @@ while (<>) {
 	$output_file = $header_name unless defined $output_file;
 
     my $out;
-    if( $output_file eq '-' ) { open $out, '>&', STDOUT }
+    if ($output_file eq '-') {
+    	$out = *STDOUT;
+    }
     else               {
-    	open( $out, ">", $output_file ) or die "can't create <$output_file>: $!";
+    	if ($opt{'i'} && -e $output_file) {
+		warn "$Program: won't clobber file '$output_file'\n";
+		exit EX_FAILURE;
+    	}
+    	unless (open $out, '>', $output_file) {
+		warn "$Program: can't create '$output_file': $!\n";
+		exit EX_FAILURE;
+    	}
 		# Quickly protect file before data is written.
 		# XXX: Does this break on sub-Unix systems, like if
 		#      it's a mode 400 or 000 file? If so, then we must
 		#      wait until after the close.
-		chmod oct($mode), $output_file or die "can't chmod <$output_file> to mode <$mode>: $!";
+    	unless (chmod oct($mode), $output_file) {
+		warn "$Program: can't chmod '$output_file' to mode '$mode': $!\n";
+		exit EX_FAILURE;
+    	}
     }
 
     binmode($out);	# winsop
@@ -56,13 +69,28 @@ LINE:
 	next LINE if /[a-z]/;
 	next LINE unless int((((ord() - 32) & 077) + 2) / 3)
 		      == int(length() / 4);
-	print $out unpack("u", $_)
-			    	or die "can't write <$output_file>: $!";
-
+	unless (print $out unpack("u", $_)) {
+	    warn "$Program: can't write '$output_file': $!\n";
+	    exit EX_FAILURE;
+	}
+    }
+    unless (close $out) {
+	warn "$Program: can't close '$output_file': $!\n";
+	exit EX_FAILURE;
+    }
+    unless ($ended) {
+	warn "$Program: missing end; '$output_file' may be truncated\n";
+	exit EX_FAILURE;
     }
-    close($out) 			or die "can't close <$output_file>: $!";
-    $ended			or die "missing end; <$output_file> may be truncated";
 }
+exit EX_SUCCESS;
+
+sub usage {
+    require Pod::Usage;
+    Pod::Usage::pod2usage({ -exitval => 1, -verbose => 0 });
+}
+
+__END__
 
 =encoding utf8
 
@@ -73,7 +101,7 @@ uudecode - decode a binary file
 =head1 SYNOPSIS
 
 	# decode to the name in the header
-	% uudecode file.uu
+	% uudecode [-i] file.uu
 
 	# decode to the name on the command line
 	% uudecode -o output.txt file.uu
@@ -84,11 +112,24 @@ uudecode - decode a binary file
 =head1 DESCRIPTION
 
 This program decodes a uuencoded file and saves the results to the file
-denoted in the header line. If that filename is C<->, the output goes to
-standard output.
+denoted in the header line.
+
+=head1 OPTIONS
+
+The following options are available:
+
+=over 4
+
+=item -i
+
+Do not overwrite files.
+
+=item -o FILE
+
+Write output to specified FILE, ignoring filename in uuencode header line.
+If FILE is '-', standard output will be used.
 
-You can override the file named in the uuencoded text by supplying a
-second command-line argument.
+=back
 
 =head1 AUTHOR