Oneliners

ONELINER

program 1
perl6 -n -e '.split(" ")[2].say' 1.txt

program 2
perl6 -e 'say [+] $*ARGFILES.lines' 2.txt

program 3
perl6 -n -e 'say $_, "\n"' 3.txt

program 4
perl6 -e 'my $i; say "{++$i}. $_" for $*IN.lines' < 4.txt

program 5
perl6 -e '$*IN.slurp.comb(/<?after \n?START\n> .*? <?before \nEND\n?>/)>>.say' < 5.txtT
Though it doesn't like to use $$ and ^^ in <?after>...

##Program 6
use v6;
my $filename = "3.txt";
say .indent(4) for $filename.IO.lines;
# still looks like a one-liner, but it's so easy in Perl 6
# also I'm working on the assumption that you didn't want blank lines with 4 spaces in the original problem, masak.

## Program 7
my $filename = "2.txt";
for $filename.IO.lines -> $line {
    say $line if $line ~~ 20..30;
}

## Program 8
sub is_palidrome ($text) {
    $text eq $text.flip;
}

my $filename = "2.txt";
for $filename.IO.lines {
   say $text if is_palindrome($text)
}
#again made an assumption that reverse was used wrong here
#otherwise this was kind of a no-op program

## Program 9
my $filename = "8.txt";
my $replacements = 0;
for $filename.IO.lines -> $line {
    $line ~~ s:g/<|w>PERL<|w>/Perl/ and $replacements++;
	$line.say;
}
print $replacements;

## Program 10
my $filename = "10.txt";
my @column-range = 2..4;
for $filename.IO.lines -> $line {
    $line.split[@column-range].join(' : ').say;
}