Hi Masato!
A few notes about your code.
On Wednesday 30 Dec 2009 09:40:56 Masato Sogame wrote:
> Hello,
> I want to replace text in file.
> So, I wrote subroutine like this:
>
> sub replace_txt {
> my ($old,$new) = @_;
Your code needs indentation.
> open (FILE,"<$ARGV[0]");
See:
http://www.perlfoundation.org/perl5/index.cgi?two_argument_open
This should be replaced with:
<<<<<<
open my $file, "<", $ARGV[0]
or die "Could not open '$file' - $!";
>>>>>>
I should note that it is bad form to access $ARGV[0] from the subroutine like
that. I would do:
<<<<<
# in top-level
my ($filename) = @ARGV;
replace_text($filename, $old_text, $new_text);
>>>>>
> while(my $line = <FILE>) {
> $line =~ s/$old/$new/g;
Unless $old is a mini-regular-expression you should use \Q and \E here:
http://perldoc.perl.org/functions/quotemeta.html
> print $line;
Do you want to print it to STDOUT?
> }
> close(FILE);
> }
>
> when I use this subroutine line this:
> &replace_txt('$a', '$b');
1. Don't use ampersand-subroutine calls:
http://www.perlfoundation.org/perl5/index.cgi?subroutines_called_with_the_ampersand
2. << '$a' >> is the literal string dollar-a. Maybe you want << "$a" >> or in
this case simply << $a >> because you don't need to stringify a single string
variable. Furthermore, you should not use $a and $b as lexical variables
because they have special meaning in
http://perldoc.perl.org/5.8.8/functions/sort.html and other functions.
> but It doesn't work. $a in $ARGV[0] is still $a.
>
> But, when I rewrite my subroutine like this:
>
> sub replace_txt {
> open (FILE,"<$ARGV[0]");
> while(my $line = <FILE>) {
> $line =~ s/\$a/\$b/g;
> print $line;
> }
> close(FILE);
> }
>
> It work fine. but I want to pass old and new text to subroutine as
> argument. How to do this?
> I search about this but I can't find any help so please help me.
>
I think the problem with your code is that you didn't use \Q and \E.
Regards,
Shlomi Fish
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