Convert bash script to perl script

[homey]

Hi,
I have a little bash diddy to show available space on a hard drive ( not partitioned space ).

Being inexperienced in perl, I sure would like some ( friendly ) input.

Here is the bash script

#!/bin/bash
##### This script calculates hard drive space.
##### example:  ./drive /dev/hda

usage()
{
   echo "Example: $0 /dev/hda"
   exit 1
}

test "$1" || usage

if ! [ -e $1 ]; then
   echo "$1 is not a valid device!"
   exit 1
fi

echo
drive=$(echo $1 | cut -d/ -f3)
drive_size=$(cat /proc/partitions | grep -e "$drive$" | awk '{print$3}')
drive_size=$(($drive_size / 1000))

IFS=$'\n'

for line in $(cat /proc/partitions | grep -e "$drive[0-9]") ; do

part=$(echo $line | awk '{print"/dev/"$4}')
size=$(echo $line | awk '{print$3}')

   if [ $size = 1 ] ; then
      echo "Partition $part  -- Extended --"
   else
      size=$(($size / 1000))
      echo  "Partition $part used  $size  MB"
      totalused=$(($totalused + $size))
   fi

done

echo
free=$(($drive_size - $totalused))
#
echo -e "Total drive size    $drive_size  MB"
echo -e "Partitioned size    $totalused  MB"
echo -e "Unpartitioned size  $free  MB"
echo
echo

Here is what I have so far in the perl script.

#!/usr/bin/perl -w
##### This script calculates hard drive space.
##### example:  ./drive /dev/hda

if($#ARGV != 0){
     die "Example: $0 /dev/sda \n";
}
if(!-e $ARGV[0]){
   die "$ARGV[0] is not a valid device. Exiting.\n";
}
my $DRIVE = $ARGV[0];

open(INFILE, "/proc/partitions")   or die "Can't open file for read: $!";
print "\n";
while (<INFILE>){

$DRIVE =~ s/\/\w+\///g;

if ($_ =~ /($DRIVE$)/){
   my ($D1, $D2, $D3, $D4, $D5) = split /\s+/;
   $drive_size = sprintf "%0d", ($D4 / 1000);

}elsif ($_ =~ /($DRIVE[0-9])/){
   my ($var1, $var2, $var3, $var4, $var5) = split /\s+/;
      if ($var4 == 1){
         print "Partition /dev/$var5  -- Extended --\n";
      }
      else {
         $var4 =  sprintf "%0d", ($var4 / 1000);
         $totalused = ($totalused += $var4);
         print "Partition /dev/$var5 used  $var4  MB\n";
       }
   }
}

    $free = ($drive_size - $totalused);
    print "\nTotal drive size    $drive_size  MB\n";
    print "Partitioned size    $totalused  MB\n";
    print "Unpartitioned size  $free  MB\n";

print "\n";
close INFILE;

[homey]

Here's another take on the perl script using format

#!/usr/bin/perl -w
##### This script calculates hard drive space.
##### example:  ./drive /dev/hda

if($#ARGV != 0){
     die "Example: $0 /dev/sda \n";
}
if(!-e $ARGV[0]){
   die "$ARGV[0] is not a valid device. Exiting.\n";
}

my $DRIVE = $ARGV[0];
print "\n";

open(INFILE, "/proc/partitions") || die "Can't open file for read: $!";
while (<INFILE>){

$DRIVE =~ s/\/\w+\///g;

if ($_ =~ /($DRIVE$)/){
   ($D1, $D2, $D3, $D4, $D5) = split /\s+/;

} elsif ($_ =~ /($DRIVE[0-9])/){
   ($var1, $var2, $var3, $var4, $var5) = split /\s+/;
      if ($var4 == 1){
         print "Partition /dev/$var5   --- Extended ---\n";
      }
      else {
         $totalused = ($totalused += $var4);
         write (STDOUT);
      }
   }
}
$~ = "ENDING";
write (STDOUT);

format STDOUT =
Partition /dev/@<<<< used @######## MB
$var5, ($var4/1000),  $var1,$var2,$var3
.

format ENDING =

Total drive size   @######## MB
($D4/1000),  $D1,$D2,$D3,$D5
Partitioned size   @######## MB
($totalused/1000)
Unpartitioned size @######## MB
(($D4-$totalused)/1000)

.
#### Just so you don't bork that last period ( . )