-p + <>???
-p + print???

Your code should be

perl -e"@lines=<>; print @lines[41900..50000];" data02.log > data03.lo
+g
[download]

As for your question,

perl -ne"next if $.<41901; print; exit if $.==50001;" data02.log > dat
+a03.log
[download]

($. is one-based while arrays are zero-based. That's why I changed the indexes by one.)

Folks thanks a lot for your answers you saved my Soul & the best solution is the one that ikegami post

time perl -ne"next if $.<41901; print; exit if $.==50001;" data02.log > data03.log

real 0m0.26s

The next one also works but is slower to run

time perl -ne "print if 41901 .. 50001" data02.log > data03.log

real 0m33.21s

An this one runs too but it takes a lot of time to run

time perl -e"@lines=<>; print @lines[41900..50000];" data02.log > data03.log

real 1m9.42s

The first stops when enough has been read. Both the second and the third read the entire file. The difference is that the third loads the entire file into memory. And since we're talking about at least 50,000 lines, you might be running into swapping issues. The third definitely has a lot more memory allocations (one per line) than the second (almost none), and those aren't cheap.

There is a conflict between using command line option, switch, '-p' which sets up a loop around the '-e' code and using '@lines=<>' which reads the whole file(s), know as a slurp, into the list. A '-p' loop looks like:

LINE:
while (<>) { #readline into $_; diamond operator
...<your '-e' code here>...
}
continue {
    print or die "-p destination $!\n";
}
[download]

Depending on what you are doing, the following may be better:

perl -pe "last if ($cnt > 50000);$_='' if ($cnt++ < 41900);" data02.lo
+g > data03.log
[download]

This one-liner prints record 41900..50000, zero relative. It will end on record 50001, which should let you have the target file a little sooner.

Good luck. -c

perl -ne "print if 41901 .. 50001" data02.log > data03.log
[download]

Nice, but that doesn't stop reading the input file after line 50001 as the OP asked.

1. To stop it from running : Cltr C

2. Another Method:

Steps:

a. Since the file is large, read each line of the file using while loop. Don't insert the entire file in an array.

b. Then, use count to keep track of each line of the file and store the line using push. In this case, you need to know which lines you to print/have in an array (or any data structure depending upon your later operations)

or use regular expressions to extract the line you want or the one you want to discard.

Example Code: Insert the Lines using regular expression

print "Enter the file name: ";
chomp( $filename = <STDIN> );
open my $INPUT, $filename or die $!;
my $count = 0;
    
while(<$INPUT>){
 $count++;
 if ( $_ =~ <pattern> ){
     push(@lineCases,$_);
    }            
}
[download]