I think the 'g' breaks '$' processing because Unix would read the whole Mac file in as a single line. (No "\n" characters.) This brings up another useful point, if Mac files are read in as a single line, then the 'g' option would be _required_ in order to process all lines.
Probably worth a check to see if Perl under Unix would actually read a whole Mac file in in one slurp. The 'g' should not, in general, have any effect on whitespace. However, the [$dos]+ would gobble up extra empty lines from a mac file, because the whole file is loaded at once. G. Wade -----Original Message----- From: Joshua Polterock [mailto:[EMAIL PROTECTED]] Sent: Thursday, March 28, 2002 10:17 AM To: Brad Baxter Cc: [EMAIL PROTECTED] Subject: Re: unix2dos and dos2unix On Thu, 28 Mar 2002, Brad Baxter wrote: > Re: > > > crlf => sub { s/[$dos$mac$unix]+/$myPlatform/og }, > > Three (hair-splitting) questions: > > 1. Isn't [$dos$mac$unix]+ going to match the same as [$dos]+? Yes. > 2. Do you need 'g'? I think this comes as a matter of taste. I generally like to globally replace strings of returns with a single new line. Including the 'g' switch compresses extra white space. Dropping the 'g' switch preserves extra white space. At least I see this when importing mac2unix. > 3. Can anyone benchmark whether s/[$dos]+$/$myPlatform/o is faster than > s/[$dos]+/$myPlatform/o? It seems like it ought to be, but my efforts > haven't proven it. I do not know if it runs faster, but the added '$' in the regular expression breaks the import I describe above when importing mac text with streams of returns. Josh > > Brad > > > On Wed, 27 Mar 2002, Joshua Polterock wrote: > > > > > On Wed, 27 Mar 2002, William R Ward wrote: > > > > > Programming by committee! This is kind of fun, in a twisted way. OK, > > > incorporating John's and Wade's suggestions: > > > > > > > All included, I believe we come to the version below. > > > > Do the '\x0D' and '\x0A', which appear to work fine on my Solaris 2.7 box, > > make this more portable? Also, do we still have platform-centricity in the > > > > my $unix = "\n"; > > > > statement? > > > > Josh > > > > #!/usr/bin/perl -w > > > > use strict; > > use File::Basename; > > > > my $dos = "\x0D\x0A"; > > my $mac = "\x0D"; > > my $unix = "\n"; > > my $myPlatform = $unix; > > my $iam = basename($0); > > > > $myPlatform = $mac if $^O =~ /mac/i; > > $myPlatform = $dos if $^O =~ /win|dos/i; > > > > my %subs = ( > > crlf => sub { s/[$dos$mac$unix]+/$myPlatform/og }, > > dos2unix => sub { s/$dos/$unix/o }, > > unix2dos => sub { s/$unix/$dos/o }, > > mac2dos => sub { s/$mac/$dos/o }, > > mac2unix => sub { s/$mac/$unix/o }, > > dos2mac => sub { s/$dos/$mac/o }, > > unix2mac => sub { s/$unix/$mac/o }, > > ); > > > > die "I do not recognize my own name." > > unless exists ($subs{$iam}); > > > > my $sub = $subs{$iam}; > > while(<STDIN>) { > > &$sub; > > print; > > } > > > > exit(0); > > > > > > >
