File Names and Extensions - The Keys to the Kingdom




       To the beginner, DOS is a little cryptic in its use of file 
       names. Study the example directory listing below and the
       notes to the right of the listing:

       PCPC     EXE    51489   5-03-86   3:36p   ---> PCPC.EXE          
       PCPR     EXE    21457   5-03-86   3:29p   ---> PCPR.EXE          
       PCPY     EXE    32017   5-03-86   3:39p   ---> PCPY.EXE          
       README            128   5-03-86  12:46p   ---> README
       NOTES565 TXT     1390   7-03-86   8:31a   ---> NOTES565.TXT
       In each case you will note the REAL file name to the right and 
       the directory listing version to the left. The point is that
       in DOS, filenames always have a name, a period or dot and an
       optional (but highly useful) extension. This is a very important 
                        KEYS TO THE SHAREWARE KINGDOM!

       Study the following list carefully, perhaps print it on paper 
       and mark it with a colored highlighter. This list contains a 
       roster of filename extensions which reveals the type of file and 
       its possible contents and application. 
                         INSTRUCTIONS OR PRINTED TEXT

       .DOC       ---------> Probable DOCumentation file
       .TXT       ---------> Probable Text (TXT) file
       .MAN       ---------> Probable MANual/instruction file
       .LST       ---------> Probable file containing a LIST.
       .PRN       ---------> Probable text file from a PRINTED source.
       .INS       ---------> Probable INSTRUCTIONS in text form.
       .HLP       ---------> Probable HELP text file.
       .          ---------> NO, EXTENSION. VERY LIKELY A TEXT FILE!
       .HST       ---------> Probable text file containing HISTORY of
                             program revisions

       READ       ---------> VERY IMPORTANT TEXT FILE
       NOTE! There are so many variations of the "READ..." theme that
       hopefully you can imagine other variations of this "READ..."
       If you stop and think about it for a minute, most of these 
       extensions and filenames offer strong clues about file contents 
       and phonetically "hint" to you what the file contains. Here are 
       some examples you might actually see. Note the "clues" that tell 
       you text or instructions are available inside the file:

             1232XX.TXT            MAKE445.DOC       SYSOPS.       
             ASEASY.LST            MANUAL.TXT        READ.         
             DATABASE.DOC          MANUAL.           AUTHOR.       
             ENTIRE.MAN            FORMFEED.MAN      VENDOR.       
             MONEY.TXT             HOMEHELP.HLP      README.       
             README.!!!            HOMEHELP.LST      README.NOW   
             READSOON.             HOMEHELP.HST      VENDORS.      
             BBM.PRN               TRY44B.DOC        MANUAL.PRN   
       Once you have determined that a file contains text or 
       instructions, you need to read the information on your screen. 
       There are three ways to do this 1) the hard old DOS way. 2) the 
       better DOS way 3) use a file viewer - easiest. 

       1) THE HARD, BUT ACCEPTABLE WAY: Use DOS TYPE command: 

       Example, A>type readme.doc   (will type the document file 
       README.DOC to the screen) 
       Example, A>type B:readme.doc   (will type the document file 
       README.DOC which is on the B: floppy drive) 

       Example, A>type readme.doc>prn  (will type the document on your 
       printer). Important! 

       Use the Ctrl and S keys together to pause rapid screen 
       scrolling. Any key touched resumes and Ctrl-S again pauses. Use 
       Ctrl and C keys (Ctrl-C) to abort the whole process! Think of 
       this reminder: Ctrl-S means "stop." Ctrl-C means "crash the 


       Here is another shortcut if the screen of information scrolls by 
       too fast to read. Use the DOS MORE filter. This MAY or MAY NOT 
       work on some computers. Switch to your hard drive where the file 
       MORE.COM usually resides in the DOS subdirectory. Now to read 
       the documentation file, for example README.DOC, on the A: drive, 
       do this: 


       Note that you are in the C: drive. You are viewing the file 
       README.DOC on the A: drive. The vertical bar | is usually on the 
       backslash key \ and is a shifted charter (uppercase). Note that 
       there are no blank spaces between the file name README.DOC, the 
       vertical bar | and the MORE command. This may or may not work on 
       all computers. MORE.COM must be pathed through the DOS directory 
       to work. More is a DOS filter. The vertical bar | is called a 
       pipe. Thus we are "piping" the output of the type command though 
       the more filter. Sounds odd, but this is one of the obscure 
       tricks of DOS! 

       3) THE BEST WAY: An external file viewer or browser. The easiest 
       and most comforable. 

       Sometimes a shareware vendor or computer club can provide a file 
       viewer. These go by many names. Popular viewers are LIST.COM,
       BROWSE.COM, VIEW.EXE, PAGE.EXE and others. These let you view 
       inside a text file and page up and down with minimum muss and 
       fuss! For our example, let's pretend you are using the popular 
       LIST.COM program.

       Example, A>list readme.doc   (will type the document file 
       README.DOC to the screen) 
       Example, A>list A:readme.doc   (will type the document file 
       README.DOC which is on the A: floppy drive to the screen) 
       Example, A>list C:\doc\readme.doc   (will type the document 
       file README.DOC which is on the C: hard drive in the \DOC 
       subdirectory to the screen) 

       Here's another tip. Sometimes a shareware program may not use a 
       file like PROGRAM.DOC or README.TXT for instructions but instead 
       a program file like README.COM or MANUAL.EXE or VPDOCS.COM. The 
       idea here is that instead of using a TEXT FILE the programmer is 
       using a program to run and display the documentation! So for 
       this variation, you simple run the program to see the 
       Example: for VPDOC.COM at the DOS prompt simply type the name 
       of the file:  C>VPDOC  (then press return/enter key)  
       Example:  For README.COM    C>README  (then press return/enter 

       Let's move on and talk about other filenames and extensions 
       which do other jobs on a computer.


       .EXE       ---------> An EXECUTABLE FILE which starts program
       .COM       ---------> A COMMAND FILE which starts program
       .BAT       ---------> BATCH FILE which starts program
       .BAS       ---------> BASIC file which can be run with
                             the aid of the GWBASIC interpreter
                             GWBASIC which is normally on your DOS
                             disk or hard drive.


       .ZIP       ---------> Compressed file, use PKUNZIP to unpack
       .ARC       ---------> Compressed file, use ARC 
       .PAK       ---------> Compressed file, use PAK
       .LZH       ---------> Compressed file, use LHARC
       .ZOO       ---------> Compressed file, use ZOO

                            OTHER USEFUL EXTENSIONS

       .BAK       --------->  A backup or duplicate file
       .DAT       --------->  A data file
       .CFG       --------->  Configuration data for program
       .WKS       --------->  Spreadsheet file
       .WK1       --------->  Spreadsheet file
       .DBF       --------->  Database file in dBase format
       .ASC       --------->  ASCII file, perhaps a basic program
                              saved in ASCII format
       .BIN       --------->  Binary file, file used by a program

       Some shareware disk vendors try to help you by putting their own 
       files on a disk with a little extra information. The following 
       file examples might offer help in text or documentation form. An 
       advanced shareware user would guess quickly that these files 
       refer to a disk from a shareware vendor or computer club library 
       and are most probably disk number 565 in a larger set of 
       programs that vendor or club offers in a library collection. 

       NOTES565 TXT     1390   7-03-86   8:31a              
       FILES565 TXT     1728   7-03-86   8:37a              
       If you buy a disk from a disk vendor named BEST VALUE SHAREWARE 
       DISTRIBUTORS you might look for files such as the following 
       which also contain text, BAT, COM or other file startup 
       Each vendor might use a different system, but watch for these 
       patterns as you list directory information on a shareware disk. 
       With the variety of methods, your best bet is to study filename 
       extensions for a few minutes and "play detective" which for some 
       folks is a bit of the interest in using shareware!


       BESTVAL.COM     1390   7-03-86   8:31a              
       BESTVAL.TXT     1728   7-03-86   8:37a              
       BV.DOC          5656   7-03-86   8:31a
       RUNBEST.COM     1777   7-03-86   8:37a
       BESTVAL.767     8787   8-9-91    9:30P

       A file ending in EXE or COM is a file which contains a 
       EXECUTABLE OR "RUNNABLE" program and is a way to start a 
       software package. 

       To start PCF.EXE do this    PCF  (then press enter).  
       For DBFKK.EXE               DBFKK (then press enter.) 
       Some files which end in BAS will need a basic interpreter such 
       as GWBASIC.EXE to operate. Example files would be GAME.BAS or 
       MUSIC.BAS. GWBASIC.EXE is usually included on your DOS disk
       which came with the computer.
       Another standard of shareware programs is to use batch files to 
       start programs. GO.BAT or MENU.BAT or START.BAT or INSTALL.BAT 
       are "batch files." Simply type the first word at the prompt to 
       Example: for file GO.BAT       GO (then press enter). 

       DOS searches a disk for programs to run in a precise order:

       HELLO.COM  ---------> Run this first if found then try 
       HELLO.EXE  ---------> to find and run this then
       HELLO.BAT  ---------> try to find and run this.
                               BASIC DATA FILES

       If you find a BASIC program file which ends in .BAS try this
       per the following example . . .

       For the file HELLO.BAS, first copy both GWBASIC.EXE
       and HELLO.BAS to a blank formatted diskette. Then issue the 


       Another alternative is to leave GWBASIC.EXE on your hard drive 
       and tell it where the basic program is located. 

       Example:     C>GWBASIC A:HELLO

       The above example assumes a copy of GWBASIC.EXE resides on your 
       hard drive and a floppy containing the basic program HELLO.BAS 
       is on the A: drive.

       The program will be loaded into GWBASIC and run. If you
       don't care for the program, try to exit if the program gives
       you a menu of choices, otherwise press CTRL-BREAK keys
       at same time which will let GWBASIC exit. You will see an
       "OK" prompt. Type the word "system" and press the return/enter 
       key to return you to DOS and leave GWBASIC. 

       Basic is a rather elegant and precise programming system if you 
       are interested! Pick up a book at your local library and you can 
       learn how to use GWBASIC.EXE on your DOS disk to write and modify 
       your own elaborate custom programs! Also investigate the
       availability of affordable Basic compiler programs which prepare 
       speedy .EXE free standing programs rather than requiring you to 
       haul out your GWBASIC.EXE file each time you wish to run the 


                      SOME EXAMPLES - OUR FIRST POP QUIZ!


       Try to puzzle through this pop quiz! Small stars next to the 
       filenames indicate an educated guess as to IMPORTANT TEXT 
       information or documentation contained within. These directory 
       lists are similar to what you might see on your screen when using 
       the DIR command when you first explore a new software disk. Brief 
       notes may follow each directory listing. 
       ** means high probability documentation is contained within
       *  means some documentation possibly is contained within

       BRUN10   EXE    58388   7-17-85   1:56p              
       BUSINESS DAT      384   5-04-86   6:42a              
       DELXTRA  BAT      128   5-03-86   6:55p              
       MSG1     TXT      384   5-03-86   7:10p  *            
       MSG2     TXT      768   5-03-86   7:23a  *            
       PAY      BAT       16   9-02-85  12:11p              
       PCPAY    DOC    64512   5-04-86   7:11a  **            
       PCPC     EXE    51489   5-03-86   3:36p              
       PCPR     EXE    21457   5-03-86   3:29p              
       PCPY     EXE    32017   5-03-86   3:39p              
       PRNTDOC  BAT      128   5-03-86   7:09p              
       README   BAT      128   5-03-86  12:46p              
       GO       BAT      668   7-03-86   8:39a              
       NOTES565 TXT     1390   7-03-86   8:31a *             
       FILES565 TXT     1728   7-03-86   8:37a *             
       Note that on the above disk the LARGEST file PCPAY.DOC contains
       64,512 bytes. Its size leads to strong suspicion it contains 
       the main documentation. Shorter files probably contain other 
       useful data. The two files at the bottom of the directory listing 
       make one suspect this disk in number 565 in a club library or 
       disk vendor collection. Sherlock Holmes would approve of our
       ASEASY   EXE   205392   7-17-90  10:29a              
       ASEASY   MSG     9636   7-16-90   6:27p *             
       ASEASY   CFG      298   1-18-90   7:47p              
       ASEASY   HLP    58346   4-25-90   9:05a **             
       HTREE    EXE     9185   4-11-90  12:36a              
       ASAU400  COM    36610   4-11-90   2:26p              
       VENDOR   DOC     3784   4-10-90  11:54p *             
       LICENSE  DOC     4133   4-11-90  12:28a *             
       ORDER    ME      4301  10-15-89  11:24p *             
       YESNO    COM       97  10-02-86   9:47p              
       SETUP    BAT     2873   7-18-90  12:26p              
       READ     ME     19512   4-12-90  11:53a **             

       The largest file which hints it contains text data would be a 
       good candidate to examine! The file SETUP.BAT suggests that 
       some intial setup or configuration of the program is necessary 
       prior to use.          
       COMFILES     <DIR>     12-05-89   4:48p              
       GOODBY            384  10-03-89   2:44p  *            
       INTRO1            512   1-11-90   8:19a  **            
       INTRO2            896  10-08-89   7:02p  **            
       MENU              640  10-03-89   3:41p              
       NEWPROD          2176  10-03-89   3:40p  *            
       MANUAL   DOC    77568   2-02-91  11:12a  **            
       QUICK    DOC    33664   2-02-91  11:10a  **            
       TUTR     DOC   109696  10-02-89   4:30p  **            
       SEBFI    COM     2270  12-10-89   2:50p              
       SEBFI    DOC     5888  12-05-89   8:04p  *            
       SEBFI    BAT      384  12-02-89   1:25p              
       LASTMIN  ANN      512  12-08-89   1:45p  *            
       GO       BAT     1362   1-31-91   6:17p              
       SEBFIM   BAT      384  12-08-89   3:05p              
       This is a disk with several important documentation files, but
       a highly unusual second subdirectory! COMFILES <DIR> contains
       other file(s) and must ALSO be examined. The DOS CD or
       change directory command must be used to examine this other
       subdirectory or file storage area of the disk. See your DOS manual.
       Most shareware authors try to stay away from using additional
       subdirectories on a disk which can confuse a beginner. The file
       LASTMIN.ANN would tell an advanced shareware user that the file
       contains "last minute announcements" and is most probably 
       a text file. TUTR.DOC probably means "tutorial document."
       QUICK.DOC is probably quick startup documentation.
       HM       EXE   306347   8-28-90  11:48a              

       This is an odd disk indeed. No documentation? Actually this
       is a special SELF-EXTRACTING file which is usually copied
       to a hard drive run with the command HM. The file will proceed 
       to unpack itself and produce several files containing 
       documentation, COM or EXE files and more! Most authors would
       include a small README file on the disk to advise you of this 
       fact, but this author has omitted even that! If you locate a 
       large EXE file, copy it to your hard drive (perhaps into
       a subdirectory named TEMP or temporary) and then run the
       file to cause it to unpack and produce all the little subfiles
       which are the main program! Shareware authors do this to 
       conserve disk space or otherwise compress large programs to
       fit onto fewer disks.
       DBATE001 EXE   185785   3-25-90   9:07a              
       DBATE002 EXE   284884   6-22-90  11:28p              
       DBATE003 EXE   244771   9-19-90   7:47p              
       READ1ST  EXE     6267  11-26-90  11:04p **             

       READ1ST.EXE is run since it is a self-extracting EXE file which 
       probably produces documentation notes. The other three files are 
       probably self-extracting files which produce three separate 
       programs. This is a case of multiple self-extracting files! A 
       clever author is highly compressing his data to save space on 
       FUNNELS  EXE    59904   9-21-84   3:01p              
       FUNNELS  DOC    14713   9-21-84   1:58p **             
       FUNNELS  INV     2432   9-21-84   3:18p              
       ATC2     BLD     4096   8-23-84   9:08p              
       ATC      EXE    50304   7-09-84  11:20a              
       AUTOEXEC BAT       11   7-12-84  10:29a              
       ATC      DAT      384   1-01-80   1:04a              
       EUCHRE   BAS    22784   7-21-84   3:09p              
       EUCHRE   DOC     3645   7-21-84   3:52p **             
       CRC      TXT     1123  11-16-84   7:06a *             
       FUNNELS  SCR      128  11-25-88  10:27a              
       A relatively simple disk. Text or documentation files indicated.
       Do you see the single basic BAS file which will require a copy
       of GWBASIC.EXE?

       Pop quiz part 2: Grab a few loose disks from any random source
       and repeat this detective process a few times and you will soon
       be a shareware GURU!