                                  FASTBAT.TXT
                            SPEEDING UP BATCH FILES
                         by Bob Unferth   Wilmette, IL

       Batch files make life a lot easier, but they are very slow.  Even
       when using batch files in RAM disks, execution time is quite
       noticeable.  It reminds me of the time when a batch file meant a
       batch of cards.  The techniques described here reduce the time
       required to execute batch file by as much as an order of magnitude.

       Execution time is closely related to the number of lines rather
       than the number of characters.  To save time put as many commands
       on one line as possible.  Some ways to do this:

       1. Instead of using a lot of lines for remarks, put what you have
       to say in a file and issue the batch command TYPE FILE.  TYPing a
       file takes less than 30% as long as echoing the same information
       from a batch file.

       2. Instead of using a lot of lines to issue commands, put all the
       commands in a FOR subcommand.  For instance, your autoexec.bat file
       might start out
                           fastdisk
                           parint
                           scrnsave
                           spool 7
                           sk
                           c:

       Instead, just say

       for %%f in (fastdisk parint scrnsave spool:7 sk c:) do %%f

       This reduces six lines to one.  In Dos 2.1, but not in 3.0, you can
       eliminate spaces and slightly decrease execution time like this:

       for %%fin(fastdisk parint scrnsave spool:7 sk c:)do%%f

       Note the colon between spool and 7. You can't have any spaces
       within the parentheses except to denote the beginning of a new
       command.

       3. When copying files use the FOR subcommand and wild cards like
       this:

       for %%fin(print v sp)docopy a:%%f???.*

       The FOR subcommand does not support wild cards within the
       parentheses.

       [PUBLIC SOFTWARE LIBRARY NOTE: Barry Simon of CalTech tells us:
       "The whole beauty of for..in..do is that it accepts wild cards
       contrary to the claim in fastbat.txt (although I did decide to
       check DOS 2 again and learned that while dos 3.x allows both
       multiple entries in the (...) with each entry wildcarded, DOS 2.x
       only allows multiple unwildcarded entires or a single wildcarded
       entries."]

       How much time the FOR subcommand will save, if any, depends on how
       the disk buffers are used while the subcommand is being executed.
       DOS remembers the entire subcommand.  It doesn't have to go back to
       disk to read more of the subcommand as it goes along.  But DOS
       doesn't remember the contents of the batch file unless it is held
       in disk buffers.  Whether or not the disk buffers keep the contents
       of the batch file depends on what you're doing between batch
       commands.





                              FASTBAT.TXT  page 2

       4. The IF subcommand supports conditional commands and the FOR
       subcommand.  For instance, you might want to see if a file exists
       and, if it does, to run several programs and then to return to the
       menu; or, if it doesn't to display a message and return to the
       menu.  A batch file for this task might look like this:

         If exist myufile goto programs
         echo File does not exist.  Try again.
         d:menu
         :programs
         myprog.ram
         second.prg
         third
         d:menu

       But it will run faster like this:

       If exist myfile for %%fin(myprog.ram second.prg third d:menu)do%%f
       for %%fin(echo d:menu)do%%f File does not exist.  Try again,

       5. When a command processor is or another batch file is invoked,
       batch processing for the first batch is terminated.  You don't need
       to exit the batch file.  For example, in the batch file fragment
       below, the command GOTO GETOUT (and probably the label :GETOUT) is
       unnecessary and will increase execution time in some cases:
                                ..
                             command c:
                             goto to getout
                                ..
                                ..
                             :getout.

       6. A fast way to get out of the middle of a batch file is to issue
       a command for another batch file, say a file called exit.  EXIT can
       contain only the command REM or just a dot or better yet nothing.
       A file that contains nothing doesn't take up any disk space.  You
       can create such a file with another batch file, say autoexec.bat,
       by inserting this command

       for %%fin(echo rem)do%%f >d:exit.bat

       The rem part of the command can be any command that doesn't look
       for parameters on the command line, e.g. cls or pause or sk.

       7. Of course, running batch files from a RAM disk is a big help.
       It's sometimes worth transferring control to a batch file that has
       been copied onto your RAM disk.  The time required for handling the
       batch operations in a RAM disk is less than a third of that
       required for a floppy.

       8. Putting an end-of-file marker (ASCII 26 or Control Z) on the
       same line and immediately after the last command, will prevent
       annoying multiple prompts at the end of batch processing.





                   This disk copy provided as a service of

                        The Public (Software) Library

         For a copy of the latest monthly software library newsletter
         and program directory, send a self-addressed, stamped (with
         two stamps), legal-size envelope or send $1 to

                        The Public (Software) Library
                                P.O.Box 35705
                                  Dept. 271
                           Houston, TX 77235-5705
