Accessing a file and modifying the contents

[keirnna]

I am trying to access a file with perl and use substitution on that files contents and print the result of that substitution.

I also need the the file I am accessing to be input on the command line like this: keirnna$ perl_script.pl file.txt

Here is what I have so far:

#!/usr/bin/perl -w

open(INPUT, "+<", "/pretend/path/file.txt")
or die "Couldn't open file..txt for reading: $!\n";
while (<INPUT>) {
$_ =~ s/really/REALLY/gi;
print;
}
close(INPUT);

However all I can get this to do is print the original file and as you can see I am forcing the use of file.txt in the script instead of naming it when I execute the program. I did a lot of searching and reading, but I haven't stumbled upon a solution yet. Sorry if this is a newb question.

[keirnna]

Actually I see now that it is printing the edited file now all I need to do is figure out how to make the unix command: perl_sript.pl text.txt to edit text.txt.

[miller]

As a one-liner:

perl -pi -e "s/really/REALLY/gi" /pretend/path/file.txt
 

[keirnna]

Thanks but I need it to be a script and not a one liner.

[miller]

Then I would suggest you use two things:

http://perldoc.perl.org/Tie/File.html
http://perldoc.perl.org/perlvar.html - Search for @ARGV

I would write it for you in a couple minutes, but those are all the links that you need and I need to go to bed.

Post if you have any problems.

[KevinADC]

since I have nothing to do at the moment:

#!/usr/bin/perl -w
 
my $file = $ARGV[0] || die "no file entered on command line";
 
{
   local @ARGV = ($file);
   local $^I = '.bac';
   while (<>) {
      s/really/REALLY/gi;
      print;
   }
}
print "finished";
 

although it's odd that you are using the "i" option unless you are looking for possible mixed-case matches of "really" instead of all lower-case. "i" tells perl to ignore case in the search pattern.