Shell Programming and Scripting

Code:

#!/usr/bin/perl
open (DATA, file.txt);
@array = <DATA>;
close (DATA);

open (DATA, ">$file.txt");
for (@array) {
      s/text/replace text/;
      push(@contents,$_);
}
seek(DATA, 0, 0);
print DATA (@contents);

close(DATA);

could someone please explain how this works. i've been trying for awhile now to find out how to open a file, replace some text and then save the file. i eventually found the code above.

however, as far as i knew 'push' placed an item onto the end of an already defined array, but in the code above @contents isn't defined.

what's going on?

regards,

matt

Perl does the "array declaration" for you.

It is implicitly created for you. In this case, it is an array with no elements inside. You can always put

@contents = ();

at the top of the script to make your intent specific (I usually do this), but it is not required.

To explicitly declare it as a lexical is in fact a better practice, so that becomes

my @contents = ();

As for your posted program, it is a very simple one (I think you have stated it yourself). If you have any specific queries, feel free to follow-up.

oh i see.

thank you all.