Shell Programming and Scripting

$
$ cat data.txt
KB0005 1019 T IFVATVPVI 0.691 PKC YES
KB0005 1036 T YFLQTSQQL 0.785 PKC YES
KB0005 1037 S FLQTSQQLK 0.585 DNAPK YES
KB0005 1045 S KQLESEGRS 0.669 PKC YES
KB0005 1045 S KQLESEGRS 0.880 unsp YES
KB204320 1019 T IFVATVPVI 0.699 PKC YES
KB204320 1036 T YFLQTSQQL 0.789 PKC YES
KB204320 1037 S FLQTSQQLK 0.589 DNAPK YES
KB204320 1045 S KQLESEGRS 0.880 unsp YES
$
$ cat testscr1.pl
#!/usr/bin/perl -w
$prevkey = "";
while (<>) {
  chomp;
  @x = split;
  $key = "$x[1]:$x[2]:$x[3]:$x[5]:$x[6]";
  $num = $x[4];
  $line = sprintf("%-10s [MESG] => %s %s %s %s %s %s\n",$x[0],$x[1],$x[2],$x[3],$x[4],$x[5],$x[6]);
  if ($prevkey eq "") {  # we are on line 1; just set $cmp to 1 and move on
    # A value of 1 means "start of comparison" - this line should be compared
    # with the next line for potential pairing. A value of 0 means
    # "end of comparison" - the comparison is over; we either found a pair or
    # found a non-repeating line.
    $cmp = 1;
  } elsif ($key eq $prevkey) {  # we found a pair
    $cmp = 0;
    # find diff
    $diff = sprintf("%6.3f",$prevnum - $num);
    # print prev and current lines if diff != 0
    if ($prevnum != $num) {
      $prevline =~ s/MESG/DIFF = $diff/;
      $line =~ s/MESG/DIFF = $diff/;
      print $prevline,$line;
    }
  } elsif ($key ne $prevkey) {  # we did not find a pair; either prev line is
                                # non repeating or we found and printed a pair
    # if $cmp equals 1 then print previous line else set $cmp to 1
    if ($cmp == 1) {
      $prevline =~ s/MESG/NO_REPETITION/;
      print $prevline;
    } else {
      $cmp = 1;
    }
  }
  $prevkey = $key;
  $prevline = $line;
  $prevnum = $num;
}
# if $cmp equals 1 then print previous line
if ($cmp == 1) {
  $prevline =~ s/MESG/NO_REPETITION/;
  print $prevline;
}
$
$ # Sorted input is absolutely essential for this perl program
$ # In the data below, all lines except line # 7 occur in pairs
$
$ sort -k2,2 -k3,3 -k4,4 -k6,6 -k7,7 data.txt
KB0005 1019 T IFVATVPVI 0.691 PKC YES
KB204320 1019 T IFVATVPVI 0.699 PKC YES
KB0005 1036 T YFLQTSQQL 0.785 PKC YES
KB204320 1036 T YFLQTSQQL 0.789 PKC YES
KB0005 1037 S FLQTSQQLK 0.585 DNAPK YES
KB204320 1037 S FLQTSQQLK 0.589 DNAPK YES
KB0005 1045 S KQLESEGRS 0.669 PKC YES
KB0005 1045 S KQLESEGRS 0.880 unsp YES
KB204320 1045 S KQLESEGRS 0.880 unsp YES
$
$ sort -k2,2 -k3,3 -k4,4 -k6,6 -k7,7 data.txt | perl testscr1.pl
KB0005     [DIFF = -0.008] => 1019 T IFVATVPVI 0.691 PKC YES
KB204320   [DIFF = -0.008] => 1019 T IFVATVPVI 0.699 PKC YES
KB0005     [DIFF = -0.004] => 1036 T YFLQTSQQL 0.785 PKC YES
KB204320   [DIFF = -0.004] => 1036 T YFLQTSQQL 0.789 PKC YES
KB0005     [DIFF = -0.004] => 1037 S FLQTSQQLK 0.585 DNAPK YES
KB204320   [DIFF = -0.004] => 1037 S FLQTSQQLK 0.589 DNAPK YES
KB0005     [NO_REPETITION] => 1045 S KQLESEGRS 0.669 PKC YES
$
$ # All lines except the last two occur in pairs
$
$ sort -k2,2 -k3,3 -k4,4 -k6,6 -k7,7 data.txt | sed -n 1,8p
KB0005 1019 T IFVATVPVI 0.691 PKC YES
KB204320 1019 T IFVATVPVI 0.699 PKC YES
KB0005 1036 T YFLQTSQQL 0.785 PKC YES
KB204320 1036 T YFLQTSQQL 0.789 PKC YES
KB0005 1037 S FLQTSQQLK 0.585 DNAPK YES
KB204320 1037 S FLQTSQQLK 0.589 DNAPK YES
KB0005 1045 S KQLESEGRS 0.669 PKC YES
KB0005 1045 S KQLESEGRS 0.880 unsp YES
$
$ sort -k2,2 -k3,3 -k4,4 -k6,6 -k7,7 data.txt | sed -n 1,8p | perl testscr1.pl
KB0005     [DIFF = -0.008] => 1019 T IFVATVPVI 0.691 PKC YES
KB204320   [DIFF = -0.008] => 1019 T IFVATVPVI 0.699 PKC YES
KB0005     [DIFF = -0.004] => 1036 T YFLQTSQQL 0.785 PKC YES
KB204320   [DIFF = -0.004] => 1036 T YFLQTSQQL 0.789 PKC YES
KB0005     [DIFF = -0.004] => 1037 S FLQTSQQLK 0.585 DNAPK YES
KB204320   [DIFF = -0.004] => 1037 S FLQTSQQLK 0.589 DNAPK YES
KB0005     [NO_REPETITION] => 1045 S KQLESEGRS 0.669 PKC YES
KB0005     [NO_REPETITION] => 1045 S KQLESEGRS 0.880 unsp YES
$
$ # No line is repeated
$
$ sed -n 1,5p data.txt
KB0005 1019 T IFVATVPVI 0.691 PKC YES
KB0005 1036 T YFLQTSQQL 0.785 PKC YES
KB0005 1037 S FLQTSQQLK 0.585 DNAPK YES
KB0005 1045 S KQLESEGRS 0.669 PKC YES
KB0005 1045 S KQLESEGRS 0.880 unsp YES
$
$ sed -n 1,5p data.txt | perl testscr1.pl
KB0005     [NO_REPETITION] => 1019 T IFVATVPVI 0.691 PKC YES
KB0005     [NO_REPETITION] => 1036 T YFLQTSQQL 0.785 PKC YES
KB0005     [NO_REPETITION] => 1037 S FLQTSQQLK 0.585 DNAPK YES
KB0005     [NO_REPETITION] => 1045 S KQLESEGRS 0.669 PKC YES
KB0005     [NO_REPETITION] => 1045 S KQLESEGRS 0.880 unsp YES
$
$ # Three pairs of lines; no single-occuring line
$
$ sort -k2,2 -k3,3 -k4,4 -k6,6 -k7,7 data.txt | sed -n 1,6p
KB0005 1019 T IFVATVPVI 0.691 PKC YES
KB204320 1019 T IFVATVPVI 0.699 PKC YES
KB0005 1036 T YFLQTSQQL 0.785 PKC YES
KB204320 1036 T YFLQTSQQL 0.789 PKC YES
KB0005 1037 S FLQTSQQLK 0.585 DNAPK YES
KB204320 1037 S FLQTSQQLK 0.589 DNAPK YES
$
$ sort -k2,2 -k3,3 -k4,4 -k6,6 -k7,7 data.txt | sed -n 1,6p | perl testscr1.pl
KB0005     [DIFF = -0.008] => 1019 T IFVATVPVI 0.691 PKC YES
KB204320   [DIFF = -0.008] => 1019 T IFVATVPVI 0.699 PKC YES
KB0005     [DIFF = -0.004] => 1036 T YFLQTSQQL 0.785 PKC YES
KB204320   [DIFF = -0.004] => 1036 T YFLQTSQQL 0.789 PKC YES
KB0005     [DIFF = -0.004] => 1037 S FLQTSQQLK 0.585 DNAPK YES
KB204320   [DIFF = -0.004] => 1037 S FLQTSQQLK 0.589 DNAPK YES
$
$ # Only one line
$
$ head -1 data.txt
KB0005 1019 T IFVATVPVI 0.691 PKC YES
$
$ head -1 data.txt | perl testscr1.pl
KB0005     [NO_REPETITION] => 1019 T IFVATVPVI 0.691 PKC YES
$
$