perl -ne 'print if 4 .. eof' file
[download]

Fifth line to tenth:

    perl -ne 'print if 5 .. 10' file
[download]

Note, in the first example the eof if mainly a visual indicator. The following would work just as well:

    perl -ne 'print if 4 .. 1' file
    perl -ne 'print if 4 .. 0' file

    # or
    perl -ne 'print if $. >= 4' file
[download]

--
John.

From the very first perl golf tournament:

perl -pe '11..exit'
(11 for 10,6 for 5, etc)

Attributable to many.

And of course, this does the exact opposite of what the OP wanted! Teach me to read the question!

edit: forgot -e switch, added caveat (thanks jmcnamara)

$ perl -ne 'print if ($. == 4)' test.txt
Line 4
$ perl -ne 'print if ( 4 < $. and $. < 11)' test.txt
Line 5
...
Line 10
[download]

I wouldn't say that using Tie::File is a good advice for this particular problem. Tie::File is rather heavy-weight, in resource usage and time needed to learn its API. Tie::File pays back your investments by giving you some handy functionality, none of which you need for the problem at hand.

It's like suggesting to use XS code to add two numbers. It's not impossible, it gives you lots of control and flexibility, but it doesn't make much sense.

-n and $. are the solutions, not Tie::File.

Abigail

This way you can substitute a line i a text file by its number:

use strict ;
my $FILE = "file.txt";
open (FILE, "$FILE");
my @TOTAL = <FILE>;
close FILE;
 $TOTAL[1] = "TEST\n";
my $FILE2 = "file2.txt";
open (FILE2, ">>$FILE2");
foreach (@TOTAL) {
print FILE2 "$_";
}
close FILE2;
[download]

1. Read the contents of your file into an array:

open(FILE, filename);
@LINES = <FILE>;
close(FILE);
[download]

Each array element now contains one line of the file.

2. Now you can operate as you wish on the desired array elements to insert/change/delete desired new lines. For example, to change the nth line;

$LINES[n] = 'some new text';
[download]

or, to take the nth to pth lines of another file and replace the nth to pth lines of your original with them:

open(FILE, filename1);
@LINES = <FILE>;
close(FILE);
open(FILE2, filename2);
@LINES2 = <FILE2>;
close(FILE2);

for $i (n .. p) {
    $LINES[$i] = $LINES2[$i];
}
[download]

3. Re-write from the array to the file:

open(FILE, filename);
for $i (0 .. $#LINES) {
    print FILE "$LINES[$i]";
}
close(FILE);
[download]

No warnings, no strictures. Bad.

use warnings;
use strict;
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You should always, yes, always, check the results of system calls for errors.

open(FILE, filename) or die "Cannot open filename:$!\n";
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There is absolutely no need in any of the examples to read the file into an array. It is faster and far less memory wasteful to loop through the file with while:

while (<FILE>)
{
  # do stuff
}
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In your 3rd example, you are not opening the file for writing, so writing will fail. This would have been caught if you had allowed warnings.

There are more problems, but since many posts above have dealt with this problem much better, I will cease now.


--
Regards,
Helgi Briem
hbriem AT simnet DOT is