SPACE 2/SPACE - Library 2 - Volume 1.iso/utility/372/utility/abzshell.doc

Text File | 1989-04-20 | 12KB | 329 lines

Most of Shell I have used can perform esoteric operation but grabs too much1111
memory space to be very useful. The last one that I have used was a 30K
program. This seem no excessive but the drawback is when loaded in memory it
freeze near to 100K.

The ABZ Shell is only 5578 bytes long, since it is written entirely in
assembler. When loaded in memory it uses just a bit more than 6K. Naturally,
from its compactness, it cannot include many complex commands. In particular
the input/output redirection is not supported. (The only time I have used
redirection is to read or print a listing, so I have included 2 commands,
SHOW and PRINT in replacement. They are similar to the Desktop dialog box
that appears when you click a non-program file).

The Shell uses 17 commands, including 2 conditional one, which can be easily
expanded since the source code is also provided. To add a new command, fill
the keyword list with the name of the command and fill the table of the
command routine address with the address (label) of the new command routine.
The keyword list can be found at 'key_w:' in the DATA section and the
address table at 'call:' in the same section.


You will find below all details about the use and particulars of the Shell.
It is to try when reading the document.

If you have any comment you can contact me via CompuServe [72467,2770], or
writet to:

    Alain Birtz
    650 Grand St-Charles, St-Paul d'Abbotsford, P.Q., Canada, J0H-1W0


You must be patient with my English, I am just learniong it, but I speak
perfectly French...
                                              Bye


--------------- Upper/Lower case typing and default pathname

When typing something in the Shell you must not be worried about using lower
or upper case letter. The Shell makes all commmands and arguments upper case
only before dealing with them. To make the job easier, the shell also
maintains the concept of pathname (folder) by default. The command PATH sets
the current pathname and then other commands can work with the file in this
folder without the use of the complete filename. For example, if the current
pathname has been set to B:\SOURCE\ASM\ by the command 'PATH B:\SOURCE\ASM\'
then to copy the file FILE1 from the drive A, you must just type 'COPY
A:FILE'. The Shell knows the file must be copied to B:\SOURCE\ASM\.



--------------- The Shell Prompt

MS-DOS or PC-DOS operating systems use Shell prompt to tell the user that the
computer is waiting for a command. Usuals prompt are something like A: or B>
The letter before the symbol ':' or '>' is the drive currently active. Our
Shell gives a bit more information by displaying the complete drive/pathname.
Morever, the display is made in reverse video to be more readable. A blank
space in included before the prompt and the cursor blinking position.



--------------- The four types of commands


The first one changes the default disk. By example A: or B:. The Shell change
the the default pathname according to the argument (A:\ or B:\). You can do
the same thing by the command PATH.


The second type is the keyword. With such a keyword you can, by example, copy
or delete one or more files. The list of keyword in presentented below.

The third type is the programs files.

Such files have extensions .PRG, .TOS, .TTP and in some case .IMG. The Shell
starts the execution of the program by just typing the name of the program
file (with or without the extentions) and some optional arguments. After the
execution the control is returned to the Shell. By example EDIT FILE1 start
the program EDIT.TTP and sent FILE1 as argument. WARNING: the TOS cannot
execute GEM program from within an other program, so don't use any GEM
program with the Shell.

The fourth type is the BAT file. This kind of file can greatly improve your
work by doing repetitive task. This is a way to extend the list of keywords.
The name BAT comes from the extension filename of these kind of files, know
as BATCH file, like in BOOT.BAT. A BAT file is built with the three previous
types of commands. Each line of a BAT file holds one keyword (and only one,
except for IF_EXIST and IF_NOT_EXIST keyword) followed or not by arguments.
These arguments can be given explicitly or by a variable. The Shell
recognizes five varaibles: %1, %2, %3, %4, %5.

A BAT file is called in the same way as a program file. You type the
filename of the BAT file (with or without .BAT extension) followed by the
arguments (like in a .TTP program). The arguments must be separated by one
or more blank spaces (character ascII 9 or 32). The Shell puts the first
argument in the variable %1, the second in %2 and so on. When the BAT
file is called, the Shell replaces every throughout in the file the variable
%1, %2,... by their argument and then executes the command of each line,
one by one. After the last one, the prompt is redisplayed and the Shell
waits for a new user command.

WARNING: don't call a BAT file within a BAT file. Only the first three
types of command are recognixed in a BAT file.

As example, you find below the BAT file I have used to assemble and link
the Shell (with AS68.PRG and ALN.PRG in the Atari developper pak).

if_exist %1 stop
if_exist %1.prg del %1.prg
if_exist %1.tos del %1.tos
if_not_exist %1.s stop
as68 -N %1.s
aln -o %1.tos %1
del %1.o



--------------- The BOOT.BAT file

The Shell can be activated at the startup by copying the ABZSHELL.TOS file
in the the AUTO folder (must be renamed ABZSHELL.PRG). When the Shell is
running for the first time, it check to see if there is if a file named
in BOOT.BATthe startup drive and if there is, it loads and executes this BAT
file. I use such a file to put in my ramdisk all the tools I need to write
my software. So I have put in the AUTO the Shell file ABZSHELL.TOS and the
boot drive C the BAT file BOOT.BAT. This one holds just the two following
lines:

if_not_exist e:ABZSHELL.TOS copy c:C_TO_D\*.* e:
e:

The first line checks if the Shell (ABZSHELL.TOS) is present in the ramdisk E.
At the startup it is not the case. So there will be an execution of the
second command in the line, that is, the copying of all files in the folder
C_TO_E to the ramdisk E. This folder hold my developpement tools. The ramdisk
I use is resistant to a Reset. After a Reset I don't need to copy my
developpement tools since thet are already in the ramdisk. This time the
first line checks for the file ABZSHELL.TOS (copied from the C_TO_D folder)
and since the file is found go directly to the second line. This one only
sets the current drive as E:, the ramdisk, and I ready to take back my work.


--------------- The keywords and their uses



-->  Dir:

Shows the directory of all files and folder in the disk and/or pathname
given in argument. If no argument is provided the directory of the current
default drive and/or pathname is shown. The date and time of file creation
and the size of the file are also given.

Example: CAT B:   or   Cat B:\SOURCE\



-->  Copy:

File copy. Take one or two arguments. If only one is provided then the
argument is the file to be copied. In this case the file is copied to the
current default folder. The second argument, if it exists, is the name of the
copied file. You can use the wildcard symbol '?' and '*'. The first matches
any single character and the second matches any string. If a wildcard symbol
is used the second argument must be the destination disk and/or pathname.
The list of all file copied are show to the screen.

Example: Copy FILE1   or  Copy FILE1 FILE2   or  Copy FILE?.* B:\SOURCE\



-->  Del:

Erases the file given in argument. As for the Copy command you can use
wildcard symbol. At each file the user must give a warrant to delete. In
fact four choices are given: Yes, No, All, Cancel. With 'Y' or 'N' the Shell
erases or not the file and goes to the next file. With 'A' all files are
automatically deleted and with 'C' the file is not deleted and the Shell
exit the DEL command. These choices are not offered if the DEL command is used
within a BAT file.

Example: Del FILE1   ou   Del B:\SOURCE\FILE?.*



-->  Rename:

This command requests two arguments. The first is the name of file to be
renamed and the second is the new filename. Wildcard symbols are prohibed.

Example: Rename B:FILE1 B:FILE2



-->  Path:

Set the disk and/or pathname by default. The disk and/or pathname is the
argument of the command.

Example: Path B:\SOURCE\



-->  Dfree:

Shows the available space (in bytes) on the disk given in argument. If no
argument is given the information is given for the current default disk.

Example: Dfree   ou  Dfree B:  ou   Dfree B:\SOURCE\



-->  Mfree:


Show the free RAM space (in bytes). No argument needed.

Example: Mfree



-->  Show:
-->  Print:

These two commands are similar to the 'SHOW or  PRINT' found in the dialog
box displayed when you click a file in a desktop directory. Both request
a filename as argument. The first command shows the file to the screen
while the second send the file to the printer. If the file is a text then
the TAB (character ascII 9) is expanded to the 8 characters.
The SHOW command displays the file continuously to the screen. You can
freeze the screen by hitting any key other than 'Q', 'q' or UNDO (these
keys stop the display and exit the SHOW command), and restart the display
by hitting the same key.
The Print command can be interrupt by hitting any key.

Example: Show FILE1   or Print B:\SOURCE\FILE2



-->  Cls:

Clear the screen and re-display the prompt at the left upper screen corner.
No argument needed.

Example: Cls




-->  Quit:

Exit the Shell and return to the Desktop or to the parent program.
No argument needed. Must be not used in a BAT file.

Example: Quit


-->  ?:

Show the list of all commands used by the Shell. No argument needed.

Example: ?


The follwing command must be used only within a BAT file.



--> Stop:

Stop the execution of the BAT file. No argument needed.

Example: Stop



--> Wait:

The execution of the BAT file is suspended. The Shell waits for a user
keyboard input. If the touched key is 'Q', 'q' or UNDO then the Shell exits
the BAT file as for a STOP command, otherwise the Shell resumes the
execution of BAT file. No argument needed.

Example: Wait



--> Write:

Display to the screen all text sitting at right of this command.
This is the only command where argument can hold blank space.

Example: Write BLA BLA BLA



-->  If_exist:
-->  If_not_exist:

In a BAT file these commands need at least two arguments.The first one
is a filename, the next must be a normal command line. This command line
will be executed only if the file exists, for IF_EXIST. In contrast the
command line will be executed only if the file does not exist, for
IF_NOT_EXIST.

Example: If_exist FILE1 Del FILE1     or   If_not_exist FILE1 Stop



--------------- Shell command sommary

MFREE           Free (RAM) memory space
DFREE           Available space on disk
QUIT            Quit The Shell
DIR             File directory
COPY            File copy
DEL             File delete
REN             Rename file
PATH            Set current default disk and/or pathname
STOP            Stop the execution od the BAT file
WRITE           Write message to the scrren
SHOW            Dsiplay the file to the screen
PRINT           Send the file to the printer
WAIT            Pause in a BAT file
IF_EXIST        Execute only if file exist
IF_NOT_EXIST    Execute only if file not exist
CLS             Clear screen
?               Show the list of all Shell command