shar: handle filename with space (#565)

* shar: handle filename with space

* shar from GNU sharutils can work with a filename with spaces, but this version can't
* Address this by quoting the filename passed to mkdir and sed
* It's not harmful to quote files which don't have a space

%perl shar '0 1' > new.shar
%sh new.shar
x - 0 1
sed: can't read 1: No such file or directory

* improve quoting of filenames containing quotes

* Introduce special quoting function which determines if a filename needs quotes
* Avoid hanging the shell by using the quoted name in the "echo" command as well as sed + mkdir (found during testing)
* Double quotes allow double quotes to be escaped within, and many other punctuation characters don't need an escape
* Some test files I inspected:
%fgrep sed  *.shar 
1.shar:sed -e 's/^X//' >"\"" <<'FUNKY_STUFF'
2.shar:sed -e 's/^X//' >"''" <<'FUNKY_STUFF'
3.shar:sed -e 's/^X//' >"0 1" <<'FUNKY_STUFF'
4.shar:sed -e 's/^X//' >"*" <<'FUNKY_STUFF'

bin/shar

@@ -25,11 +25,6 @@ use constant EX_FAILURE => 1;
 
 my $Program = basename($0);
 
-sub usage {
-    warn "usage: $Program file...\n";
-    exit EX_FAILURE;
-}
-
 getopts('') or usage();
 @ARGV or usage();
 binmode STDOUT;
@@ -41,9 +36,14 @@ print '# --cut here--
 
 my $done = 0;
 ARGUMENT: for my $f ( @ARGV ) {
+    if (length($f) == 0) {
+	warn "$Program: empty file name\n";
+	next ARGUMENT;
+    }
+    my $quoted = quotefile($f);
     if (-d $f) {
-	print "echo x - $f/\n";
-	print "mkdir -p $f\n";
+	print "echo x - $quoted/\n";
+	print "mkdir -p $quoted\n";
 	$done++;
 	next ARGUMENT;
     }
@@ -53,7 +53,7 @@ ARGUMENT: for my $f ( @ARGV ) {
     }
     binmode FH;
 
-    print "echo x - $f\n";
+    print "echo x - $quoted\n";
     if (-B $f) {
 	my $mode = (stat $f)[2];
 	$mode = (join '', 0, ($mode&0700)>>6, ($mode&0070)>>3, ($mode&0007));
@@ -63,11 +63,14 @@ ARGUMENT: for my $f ( @ARGV ) {
 	print pack 'u', $block while read FH, $block, 45;
 	print "end\n";
     } else {
-	print "sed -e 's/^X//' >$f <<'FUNKY_STUFF'\n";
+	print "sed -e 's/^X//' >$quoted <<'FUNKY_STUFF'\n";
 	print 'X', $_ while ( <FH> );
     }
     print "FUNKY_STUFF\n";
-    close(FH);
+    unless (close FH) {
+	warn "$Program: can't close '$f': $!\n";
+	next ARGUMENT;
+    }
     $done++;
 }
 if ($done == 0) {
@@ -76,6 +79,20 @@ if ($done == 0) {
 }
 exit EX_SUCCESS;
 
+sub usage {
+    warn "usage: $Program file...\n";
+    exit EX_FAILURE;
+}
+
+sub quotefile {
+    my $name = shift;
+    if ($name =~ m/[\s\'\"\(\)\[\]\{\}\;\:\*]/) {
+	$name =~ s/\"/\\\"/g;
+	$name = "\"$name\"";
+    }
+    return $name;
+}
+
 __END__
 
 =head1 NAME