How can I find out the approximate number of .COM names by looking at
the .COM zone file. Are there any programs that will interpret the
data in the .COM zone file ?

Where did you find the .COM zone file? I understand this file is HUGE.
Anyway, it should not be difficult to write a small program that will
interpret the .COM zone file. A simple UNIX shell script will do. But
I also searched the web, and found out there should be about 22.5
million registered domain names in the .COM zone - out of about 35
million domain names in total. But I'm not sure if this information is
up-to-date.

Maybe if you could post several lines of that file here, we could find a solution.

Wanted

Well, I'm not sure if you want to interpret your zone file just to
interpret it, or you want to find out how many domains are registered.
If you would like to find out how many domains are registered goto
http://www.domainstats.com I believe the current numbers are per
Domain Stats

INTERNATIONAL (COM) 21246483  
INTERNATIONAL (EDU) 7396  
INTERNATIONAL (NET) 3591591  
INTERNATIONAL (ORG) 2325580  
United Kingdom (CO.UK) 3406345 

I hope this Helps,
Dan

NTLORD, i am interested in knowing how many domain names are
registered / alive etc. on a given day. Do you know how often the
domainstats.com site is updated ?

Thanks.

Here is the process to obtain the zone file and a simple way to
interpret the data.

1. Fill and fax back the Verisign-GRS paperwork required to download
the zone files. The form can be found at:
http://www.verisign-grs.com/tld/tld-agreement.pdf
(you will need to specify the host you will use to connect to the
versign FTP server to download the zone info).

2. Assuming your paperwork is approved follow the instructions given.
From the host you preselected connect to rz.versign-grs.com (via FTP)
with the userid and password assigned to you. GET a gzipped copy of
the .com zone file.

3. Unzip the file.

On a unix machine the best way to get a fairly good count of the
number of registered .com domains is:

> cat com.zone | wc -l

Take the result from this command and divide by two. This will not be
the exact answer because it counts a bit of header data and it assumes
each domain has exactly 2 assigned nameservers. However, it will be
relatively accurate. To get an exact count you could pipe the cat
output to awk and run a regular expression to parse out only the data
matching *.COM. (not valid regexp syntax) and pipe that result to the
'uniq' command before piping it to 'wc -l'

The file format is as follows (This is a snippit of the April 26, 2002
.com
zone file. The orgininal file was 47,326,483 lines long: 

;File start: 6179
; The use of the Data contained in Network Solutions' aggregated
; .com, .org, and .net top-level domain zone files (including the
checksum
; files) is subject to the restrictions described in the access
Agreement
; with Network Solutions.

COM. IN    SOA    A.GTLD-SERVERS.NET. NSTLD.VERISIGN-GRS.COM. (
                  2002042600 ;serial
                  1800 ;refresh every 30 min
                  900 ;retry every 15 min
                  604800 ;expire after a week
                  86400 ;minimum of a day
                  )
COM. 518400 IN NS A.GTLD-SERVERS.NET.
COM. 518400 IN NS G.GTLD-SERVERS.NET.
COM. 518400 IN NS H.GTLD-SERVERS.NET.
COM. 518400 IN NS C.GTLD-SERVERS.NET.
COM. 518400 IN NS I.GTLD-SERVERS.NET.
COM. 518400 IN NS B.GTLD-SERVERS.NET.
COM. 518400 IN NS D.GTLD-SERVERS.NET.
COM. 518400 IN NS L.GTLD-SERVERS.NET.
COM. 518400 IN NS F.GTLD-SERVERS.NET.
COM. 518400 IN NS J.GTLD-SERVERS.NET.
COM. 518400 IN NS K.GTLD-SERVERS.NET.
COM. 518400 IN NS E.GTLD-SERVERS.NET.
COM. 518400 IN NS M.GTLD-SERVERS.NET.
A.GTLD-SERVERS.NET. 518400 IN A 192.5.6.30
G.GTLD-SERVERS.NET. 518400 IN A 192.42.93.30
H.GTLD-SERVERS.NET. 518400 IN A 192.54.112.30
C.GTLD-SERVERS.NET. 518400 IN A 192.26.92.30
I.GTLD-SERVERS.NET. 518400 IN A 192.43.172.30
B.GTLD-SERVERS.NET. 518400 IN A 192.33.14.30
D.GTLD-SERVERS.NET. 518400 IN A 192.31.80.30
L.GTLD-SERVERS.NET. 518400 IN A 192.41.162.30
F.GTLD-SERVERS.NET. 518400 IN A 192.35.51.30
J.GTLD-SERVERS.NET. 518400 IN A 210.132.100.101
K.GTLD-SERVERS.NET. 518400 IN A 213.177.194.5
E.GTLD-SERVERS.NET. 518400 IN A 192.12.94.30
M.GTLD-SERVERS.NET. 518400 IN A 192.55.83.30
0-------------------------------------------------------------0.COM.
172800 IN N
S NS1.DOMAINIT.COM.
0-------------------------------------------------------------0.COM.
172800 IN N
S NS2.DOMAINIT.COM.
0-------------------------------------------------------------2.COM.
172800 IN N
S DNS1.NAMESECURE.COM.
0-------------------------------------------------------------2.COM.
172800 IN N
S DNS2.NAMESECURE.COM.
0-------------------------------------------------------------3.COM.
172800 IN N
S DNS1.NAMESECURE.COM.
0-------------------------------------------------------------3.COM.
172800 IN N
S DNS2.NAMESECURE.COM.
0-------------------------------------------------------------4.COM.
172800 IN N
S DNS1.NAMESECURE.COM.
0-------------------------------------------------------------4.COM.
172800 IN N
S DNS2.NAMESECURE.COM.
0-------------------------------------------------------------5.COM.
172800 IN N
S FNS.FROGSMART.NET.
0-------------------------------------------------------------5.COM.
172800 IN N
S SNS.FROGSMART.NET.
0------------------------------------------------------------0.COM.
172800 IN NS
 DNS1.NAMESECURE.COM.
0------------------------------------------------------------0.COM.
172800 IN NS
 DNS2.NAMESECURE.COM.
0-----------------------------------------------------------0.COM.
172800 IN NS
DNS1.NAMESECURE.COM.
0-----------------------------------------------------------0.COM.
172800 IN NS
DNS2.NAMESECURE.COM.
0----------------------------------------------------------0.COM.
172800 IN NS D
NS1.NAMESECURE.COM.
0----------------------------------------------------------0.COM.
172800 IN NS D
NS2.NAMESECURE.COM.
0---------------------------------------------------------0.COM.
172800 IN NS DN
S1.NAMESECURE.COM.
0---------------------------------------------------------0.COM.
172800 IN NS DN
S2.NAMESECURE.COM.
0---------------------------------------------------------SAUNA.COM.
172800 IN N
S NS0.DIRECTNIC.COM.
0---------------------------------------------------------SAUNA.COM.
172800 IN N
S NS1.DIRECTNIC.COM.
0--------------------------------------------------------0.COM. 172800
IN NS DNS
1.NAMESECURE.COM.
0--------------------------------------------------------0.COM. 172800
IN NS DNS
2.NAMESECURE.COM.
0------------------------------------------------------EXERCISE.COM.
172800 IN N
S NS0.DIRECTNIC.COM.
0------------------------------------------------------EXERCISE.COM.
172800 IN N
S NS1.DIRECTNIC.COM.
0---------------------0.COM. 172800 IN NS NS0.DIRECTNIC.COM.
0---------------------0.COM. 172800 IN NS NS1.DIRECTNIC.COM.
0----------------0.COM. 172800 IN NS NS0.DIRECTNIC.COM.
0----------------0.COM. 172800 IN NS NS1.DIRECTNIC.COM.
0----------------SAUNA.COM. 172800 IN NS NS0.DIRECTNIC.COM.
0----------------SAUNA.COM. 172800 IN NS NS1.DIRECTNIC.COM.
0--------------0-0-0-0.COM. 172800 IN NS NS1.CONEPUPPY.COM.
0--------------0-0-0-0.COM. 172800 IN NS NS2.CONEPUPPY.COM.
0-------------EXERCISE.COM. 172800 IN NS NS0.DIRECTNIC.COM.
0-------------EXERCISE.COM. 172800 IN NS NS1.DIRECTNIC.COM.
0----------SAUNAHEATER.COM. 172800 IN NS NS0.DIRECTNIC.COM.
0----------SAUNAHEATER.COM. 172800 IN NS NS1.DIRECTNIC.COM.
0---------0.COM. 172800 IN NS NS0.DIRECTNIC.COM.
0---------0.COM. 172800 IN NS NS1.DIRECTNIC.COM.
0-----60.COM. 172800 IN NS NS.BULKREGISTER.COM.
0-----60.COM. 172800 IN NS NS2.BULKREGISTER.COM.
0----0.COM. 172800 IN NS NS1.DIGITALDNSSERVER.COM.
0----0.COM. 172800 IN NS NS2.DIGITALDNSSERVER.COM.
0---0.COM. 172800 IN NS DNS1.ENOM.COM.
0---0.COM. 172800 IN NS DNS2.ENOM.COM.
0---0.COM. 172800 IN NS DNS3.ENOM.COM.
0---0.COM. 172800 IN NS DNS4.ENOM.COM.
0---1.COM. 172800 IN NS NS1.92Z.COM.
0---1.COM. 172800 IN NS NS3.7TS.COM.
0--0--0.COM. 172800 IN NS A.NS.JOKER.COM.
0--0--0.COM. 172800 IN NS B.NS.JOKER.COM.
0--0--0.COM. 172800 IN NS C.NS.JOKER.COM.
0--0--GPS.COM. 172800 IN NS NS000.NS0.COM.