aa|3|1
aa|4|2
bb|3|1
bb|4|1
cc|3|26
cc|4|1
aa|8|5
aa|7|9

#!/usr/bin/perl -w
use strict;

my $cur_dir = $ENV{PWD};
my $filename = $cur_dir."/file008";
my ($record,@fields,%hash,$key,$flg);

open(FILE,"<$filename") or die"open: $!";

while( defined( $record = <FILE> ) ) {
  chomp $record;
  @fields=split(/\|/,$record);

  # New key and not the 1st one ?
  if( (defined($key)) && ($key ne $fields[0]) ) {
    $flg=1;
  } else {
    $flg=0;
  }

  # Processing new key or same key
  if( $flg == 1) {
    # new key printing previous one and processing new one
    print "$key$hash{$key}\n";
    delete( $hash{$key} );
    $key=$fields[0];
    $hash{$key}="\|$fields[1]\|$fields[2]";
  } else {
    # processing existing key
    $key=$fields[0];
    $hash{$key}.="\|$fields[1]\|$fields[2]";
  }
}

# Printing last key if needed
if( $flg == 0) {
  print "$key$hash{$key}\n";
}

close(FILE);

aa|3|1|4|2
bb|3|1|4|1
cc|3|26|4|1
aa|8|5|7|9