#!/usr/bin/perl -w

use strict;
my @devices;
$/ = "\n  ";
while (my $lines = <DATA>) {
    my %hash;
    if ($lines =~ m/Bus (\d+), device (\d+), function (\d+):/) {
        $hash{bus} = $1;
        $hash{device} = $2;
        $hash{function} = $3;
    }
    ## parse other lines ...
    push @devices,\%hash;
}

# use @devices

# /proc/pci from
# http://web.gnu.walfield.org/mail-archive/linux-kernel/1999-October/0
+315.html
__END__
PCI devices found: 
  Bus 0, device 0, function 0: 
    Host bridge: Intel Unknown device (rev 3). 
      Vendor id=8086. Device id=7190. 
      Medium devsel. Master Capable. Latency=64. 
      Prefetchable 32 bit memory at 0xe6000000 [0xe6000008]. 
  Bus 0, device 1, function 0: 
    PCI bridge: Intel Unknown device (rev 3). 
      Vendor id=8086. Device id=7191. 
      Medium devsel. Master Capable. Latency=64. Min Gnt=136. 
  Bus 0, device 7, function 0: 
    ISA bridge: Intel 82371AB PIIX4 ISA (rev 2). 
      Medium devsel. Fast back-to-back capable. Master Capable. No bur
+sts. 
  Bus 0, device 7, function 1: 
    IDE interface: Intel 82371AB PIIX4 IDE (rev 1). 
      Medium devsel. Fast back-to-back capable. Master Capable. Latenc
+y=64. 
      I/O at 0xf000 [0xf001]. 
  Bus 0, device 7, function 2: 
    USB Controller: Intel 82371AB PIIX4 USB (rev 1). 
      Medium devsel. Fast back-to-back capable. Master Capable. Latenc
+y=64. 
      I/O at 0xe000 [0xe001]. 
  Bus 0, device 7, function 3: 
    Bridge: Intel 82371AB PIIX4 ACPI (rev 2). 
      Medium devsel. Fast back-to-back capable. 
  Bus 0, device 9, function 0: 
    Ethernet controller: Realtek 8029 (rev 0). 
      Medium devsel. IRQ 12. 
      I/O at 0xe400 [0xe401]. 
  Bus 0, device 11, function 0: 
    Non-VGA device: NCR 53c810 (rev 1). 
      Medium devsel. IRQ 10. Master Capable. Latency=64. 
      I/O at 0xe800 [0xe801]. 
      Non-prefetchable 32 bit memory at 0xe7000000 [0xe7000000]. 
  Bus 1, device 0, function 0: 
    VGA compatible controller: Matrox Unknown device (rev 3). 
      Vendor id=102b. Device id=525. 
      Medium devsel. Fast back-to-back capable. IRQ 11. Master Capable
+. Latency=64. Min Gnt=16.Max Lat=32. 
      Prefetchable 32 bit memory at 0xe4000000 [0xe4000008]. 
      Non-prefetchable 32 bit memory at 0xe0000000 [0xe0000000]. 
      Non-prefetchable 32 bit memory at 0xe1000000 [0xe1000000].
[download]

In this case, you treat /proc/pci per line. Perhaps you would like to read the file by records, like:

  # example of a full record
  Bus 0, device 0, function 0: 
    Host bridge: Intel Unknown device (rev 3). 
      Vendor id=8086. Device id=7190. 
      Medium devsel. Master Capable. Latency=64. 
      Prefetchable 32 bit memory at 0xe6000000 [0xe6000008].
[download]

If so, you only need to make a slight modification to MZSanford code:

use strict;
my @devices;
undef $/;
foreach (split /\n\s\s\b/, <DATA>) {
    # you now have the whole record in $_
    # do with it as you please
}
<snip>
[download]

- Good luck

The machine is a standard Intel Pentium PC. The section of /proc/pci I am interested in, looks like this:-

Bus 0, device 15, function 0
Unknown class: Unknown vendor Unknown device (rev 1).
Vendor id=135a. Device id=61.
Medium devsel. Fast back-to-back capable. IRQ 9
Non-prefetchable 32 bit memory at 0x412000000
I/O at 0x2080
I/O at 0x2400
I/O at 0x2410
Blah..
Blah..
[download]

I am interested in seeking out devices with this vendor and device id and then getting just the I/O entires (just 2nd and 3rd though, not interested in the first. I tried the posted example but got:

Name "main::DATA" used only once: possible type at line 6
readline() on closed filehandle main::DATA at line 6..
[download]

Ahhh...

The stuff that he put after the __END__ line gets read into the filehandle called DATA. So, what you want to do is open up /proc/pci yourself (since you won't have the data embedded in your script.)

Try putting this line before the while loop:
open(DATA, '/proc/pci') or die "Can't open /proc/pci: $!";