use strict;
use warnings;

my @lines = (
'3 | 1853 1239 293 293 293 293 293 293 292', 
'5 | 1853 1239 293 293 293 293 293 293 3428'
);

foreach my $line ( @lines ) {
    my ( $id, $path ) = split /\s+\|\s+/, $line, 2;
   
    $path = join ' ', unique( split / /, $path );
    print "$id | $path\n";
}

sub unique {
    my %h = ();
    return grep { !$h{$_}++ } @_;
}