How to implement Linux tail command in Perl

Krishna S November 20, 2014

I have tried writing a Perl script to simulate Linux tail command - print last n lines from a file. This is one of the common interview questions in Perl. This can be extended to print selected lines of other Linux commands like head. It works perfectly fine.


print "\nImplements linux tail command in perl \n\n";

$file   =  $ARGV[0];
$n = $ARGV[1];
open(FILE, $file);
@arr = ;
close(FILE);
$length  = scalar(@arr);
$n = $length  - $n;

while($n<$length )
{
print $arr[$n];
$n =$n + 1;
}

Comment  below if you have a better option

Krishna S

Posted by Krishna S

Working as a software engineer, started blogging to share the information. My posts usually includes, tips and tricks on daily computer use, and how to series on MS Office.

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3 Comments

  1. Alien CodersNovember 26, 2014 at 4:57 PM

    how about implementing tail -f after this :)
    while(1){
    $prev_size = -s $file;
    tailf($file,10) if (-s $file > $prev_size);
    }

    tailf() will be your written code with little updates :)

    ReplyDelete
  2. UnknownOctober 3, 2018 at 8:38 PM

    We can also write tail implementation in Perl as below

    my $maxline = 10;
    if(scalar(@ARGV) == 2){
    $maxline = shift;
    }

    my $file_name =shift;
    open(FILE, "$file_name") || die "Can't open file. Error: $!\n";
    my @arr = ;
    close(FILE);
    my $index=scalar(@arr)-$maxline;
    print @arr[$index .. $#arr];

    ReplyDelete
  3. selimAugust 1, 2023 at 9:29 AM

    gümüşhane
    bilecik
    erzincan
    nevşehir
    niğde
    İR5GN

    ReplyDelete