Shell Programming and Scripting

BOX
-1.000000 -1.000000 0.000000
30.00000 14.00000 0.1000000
0.000000 0.000000 0.000000
0.000000
0.000000
CYLINDER
3.595000 2.995000 0.000000
0.5100000 2.000000
Z
0.000000 0.000000
0.000000

_Box -1.000000,-1.000000,0.000000 30.00000 14.00000 0.1000000
_Cylinder 3.595000,2.995000,0.000000 0.5100000 2.000000

$infile="box_cyl.txt";
open(IN,$infile);
@lines=<IN>;

for ($i=1;$i<=$#lines;$i++){
	if($lines[$i] =~ 'CYLINDER'){
		@line1 = split (/ /,$lines[$i+2]);
                @line2 = split (/ /,$lines[$i+3]);
	} 
        elsif($lines[$i] =~ 'BOX'){
		@line1 = split (/ /,$lines[$i+2]);
                @line2 = split (/ /,$lines[$i+3]);
	}
}

#!/usr/bin/perl

use strict;
use warnings;

my $in="file";

open my $fh, '<', $in or die "Could not read $in: $!\n";

# start reading the file
while ( my $line = <$fh> ) {

    # find line with pattern BOX or CYLINDER
    if ( $line =~ /BOX|CYLINDER/ ) {

        chomp $line; # remove newline if exist

        my @captured_lines; # create a empty work space

        push @captured_lines, $line; # first store BOX or CYLINDER

        # we know the next two lines belongs with BOX or CYLINDER
        # let's get them
        foreach (1..2) {
            my $extra_line = <$fh>;
            chomp $extra_line;
            push @captured_lines, $extra_line;
        }

        # manipulate the strings
        $captured_lines[0] =~ s/(\w+)/_\u\L$1/g; # convert BOX into _Box and
                                                 # CYLINDER into _Cylinder
        $captured_lines[1] =~ s/ /,/g; # convert the spaces to `,' for
                                       # the first line after match

        print join (" ", @captured_lines) . "\n"; # display processed block
    }

    # optional: stop reading the file after manipulating CYLINDER
    if ( $line =~ /CYLINDER/ ) { last }
}
close $fh;