Re: Performing a tail(1) in Perl (reading the last N lines of a file)

Hello all, I was myself having some trouble to get information from the last lines of a file without having to go through the whole thing to get the, and stumbled upon this topic, and while reading I had the following idea:

open (FILE, $file);
my @file = <FILE>;
close FILE;
for (my $count = ( (scalar @file) -1); $count >= 0; $count--){
#my $line = $file[count]; optional
   # do what you gotta do

   # to end the loop abruptly, just do: $count = -1; 
   # This can be done from an else (if you are searching
   # patters with if's. 
   #Or you can use another, increasing counter, so you can
   # choose the number of lines to look at, say 12, then:
   # if ($count_2 > 12) {$count = -1}
}
[download]

I'd like advice and critics on the code above, what say you Monks? ps: I'm still a newbie, and haven't tried the code for time or memory use(Don't know how).

Comment on Re: Performing a tail(1) in Perl (reading the last N lines of a file) Download Code

Replies are listed 'Best First'.
Re^2: Performing a tail(1) in Perl (reading the last N lines of a file) by Anonymous Monk on Aug 30, 2011 at 07:20 UTC
Hi, new questions go in Seekers Of Perl Wisdom because grinder, whom you asked a question, hasn't been here in 2 years. The node to which you replied is 9 years old. Welcome, see The Perl Monks Guide to the Monastery, see How do I post a question effectively?, Where should I post X? Now , regarding your code, I recommend you read grinders meditation until it starts making sense. Reading the whole file into memory will work for small files only. I might write the same code as `for my $index ( 1 .. 12 ){ my $line = $lines[ - $index ]; }` [download]	[reply] [d/l]

Replies are listed 'Best First'.

Re^2: Performing a tail(1) in Perl (reading the last N lines of a file)
by Anonymous Monk on Aug 30, 2011 at 07:20 UTC

Hi, new questions go in Seekers Of Perl Wisdom because

grinder, whom you asked a question, hasn't been here in 2 years.

The node to which you replied is 9 years old.

Welcome, see The Perl Monks Guide to the Monastery, see How do I post a question effectively?, Where should I post X?

Now , regarding your code, I recommend you read grinders meditation until it starts making sense. Reading the whole file into memory will work for small files only. I might write the same code as

for my $index ( 1 .. 12 ){
    my $line = $lines[ - $index ];
}
[download]

[reply]
[d/l]