Shell Programming and Scripting

<Attribute1 name><x amount of white spaces><Atribute value>
<Attribute2 name><x amount of white spaces><Atribute value>
<Attribute3 name><x amount of white spaces><Atribute value>
<Attribute4 name><x amount of white spaces><Atribute value>
<Attribute5 name><x amount of white spaces><Atribute value>

A   1
B   2
C  3
D   4
E  5
B  4
C    3
A  5
E  1
D  2

sub query {
        open (OUTPUT, "su - oracle -cf 'source .profile; sqlplus $user/$passwd \@$sql_file'|") || die "Can open SQL\n";
        while (<OUTPUT>) {
                chop;
                ($rubbish,$value) = split(/\s+/);
                if (/^A/){
                        $list[0] = $value;
                } elsif (/B/){
                        $list[1] = $value;
                } elsif ( /C/ ){
                        $list[2] = "$value";
                } elsif ( /D/ ){
                        $list[3] = "$value";
                } elsif ( /E/ ){
                        $list[4] = "$value";
                } else { next;}
                push ( @array, \@list );
        }
        close(OUTPUT);
}
sub printSubs {
        $" = ",";
        for $a (@array){
                print "@$a\n";
        }
}

#!/usr/bin/perl

open (FH,"Outputfile") or die "FAIL- $!\n";
while (<FH>) {
chomp;
@fields=split(/\s+/);
push(@{$fields[0]},$fields[1]);
$hash{$fields[0]}=\@{$fields[0]};
}

for($i=0;$i<($./5);$i++) {
foreach (sort(keys(%hash))) {
printf "%s ",$hash{$_}[$i];
}
print "\n";
}

while (<OUTPUT>) {
 chomp;
 ($rubbish,$value) = split(/\s+/);
 if (/^A/){
   $list[0] = $value;
 } elsif (/B/){
   $list[1] = $value;
 } elsif (/C/){
   $list[2] = $value;
 } elsif (/D/){
   $list[3] = $value;
 } elsif (/E/){
   $list[4] = $value;
 } else { next }
 print join(",", @list),"\n" if ($.%5 == 0); 
}

$
$
$ # display the content of the data file "f2"
$
$ cat f2
A   1
B   2
C  3
D   4
E  5
B  4
C    3
A  5
E  1
D  2
$
$
$ # display the content of the Perl program "f2.pl"
$
$ cat -n f2.pl
    1  #!perl -w
    2  my $rubbish;
    3  $file="f2";
    4  open (OUTPUT, "<", $file) || die "Can't open $file\n";
    5  while (<OUTPUT>) {
    6    chomp;
    7    ($rubbish,$value) = split(/\s+/);
    8    if (/^A/){
    9      $list[0] = $value;
   10    } elsif (/B/){
   11      $list[1] = $value;
   12    } elsif (/C/){
   13      $list[2] = $value;
   14    } elsif (/D/){
   15      $list[3] = $value;
   16    } elsif (/E/){
   17      $list[4] = $value;
   18    } else { next }
   19    print join(",", @list),"\n" if ($.%5 == 0);
   20  }
   21  close(OUTPUT);
   22
$
$
$ # Run the Perl program
$
$ perl f2.pl
1,2,3,4,5
5,4,3,2,1
$
$

After 1st record is processed, @list = (1)             and \@list = pointer to @list i.e. it points to (1)
After 2nd record is processed, @list = (1, 2)          and \@list = pointer to @list i.e. it points to (1, 2)
After 3rd record is processed, @list = (1, 2, 3)       and \@list = pointer to @list i.e. it points to (1, 2, 3)
After 4th record is processed, @list = (1, 2, 3, 4)    and \@list = pointer to @list i.e. it points to (1, 2, 3, 4)
After 5th record is processed, @list = (1, 2, 3, 4, 5) and \@list = pointer to @list i.e. it points to (1, 2, 3, 4, 5)