C/C++ Interactive Guide/c-cplusplus-interactive-guide.iso/c_ref/csource3/185_01/hsh.doc

Text File | 1985-08-21 | 9.8 KB | 331 lines

        HSH.DOC    Version 1.1  6 Oct 85                   Page 1


        Copyright 1985  Michael M Rubenstein

        This software and the accompanying documentation may be
        distributed freely for noncommercial use.



        Credits.

        ZCPR3 is a trademark of Richard L. Conn.

        CP/M is a trademark of Digital Research Incorporated.

        WordStar is a trademark of Micropro International Corporation.

        C/80 is a trademark of The Software Toolworks.



        Modifications.

        1.1       Fixed handling of wrap around when the history is full.



        Description.

        HSH is a history processing ZCPR3 shell.  It provides the ability
        to recall and edit previous commands and allows much more
        sophisticated editing than is found in the normal CP/M or ZCPR3
        command processor.

        For example, with HSH if the command

                  mcpy b:=*.dat

        is typed and one notices that the command should have been
        "mcopy", one can simply move the cursor back to the "p" and
        insert an "o".  If the command is entered and an error message
        received, the command can be recalled and edited in the same
        manner.

        Unlike many other shells, HSH is intended to be a normal
        operating environment.  Therefore, it generates no noise unless
        it's special features are invoked.  For the most part, the user
        sees the same results as if HSH were not present.

        HSH operates best in conjunction with a ram disk or a high speed
        hard disk.  Those with slower disks are likely to find response
        lethargic with HSH present.



        Requirements.









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        HSH requires ZCPR3 with external command line and shell stack.
        The current version requires a video terminal which automatically
        wraps lines and which allows backspacing from column one to the
        end of the previous line.  About 8K of disk space is required for
        the program.  The history file requires 384 bytes plus 256 bytes
        per history line being kept.  The default of 10 history lines
        requires 4K disk space.  The program and history file should be
        on a ram disk or high speed hard disk for best results.



        Running HSH.

        Before running HSH, it must be installed with Z3INS in the same
        way as any other ZCPR3 utility.

        HSH is run with the command

                  hsh

        One operand, the number of history lines to keep (from 0 through
        100) may be included, e.g.,

                  hsh 50

        If no operand appears on the command line, HSH will use the value
        from the history file, HSH.VAR, or 10 if there is no history
        file.  This allows one to exit HSH and return without loosing the
        history.  If a numeric operand does appear, a new history file
        will be created (the old will be deleted) and any previous
        history will be lost.

        If there is no problem, HSH will install itself and display a
        sign on message.  HSH may be started from a submit file, in which
        case the submit file will complete before HSH actually takes
        control.

        HSH searches for itself (by whatever name it is called) along the
        current path.  Normally the current directory is not searched
        unless it is explicitly included on the path.  This may be
        changed by patching the byte at 010Bh to nonzero.

        HSH puts the history file on the "root" directory -- the last
        directory in the search path.  For best results, the "root"
        directory and the copy of HSH that it finds in searching for
        itself should both be on a ram disk.  I use a path like

                  RAMDISK $$ ROOT RAMDISK

        so critical programs are found on the ram disk first.  Note that
        the "root" directory with this path is RAMDISK, not ROOT.

        The HSH prompt looks exactly like the usual ZCPR3 prompt.
        Commands may be typed and will be executed normally.  The only
        exceptions are the SAVE, GET, GO, and JUMP commands.  These will








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        not give the desired effect if entered as single commands at the
        prompt because HSH is in the TPA.  For example, the sequence

                  A0>ddt test.com
                  A0>save 16 newtest.com

        will result in the first 16 pages of HSH being saved.  To get the
        desired effect, one must plan ahead and type multiple commands

                  A0>ddt test.com;save 16 newtest.com

        which works since HSH does not regain control between the two
        commands.

        HSH recognizes two characters as special if they appear as the
        first character of a typed line.   Both are recognized
        immediately (i.e., no carriage return is necessary).

             <ESC> -   (Escape key).  Exit HSH.

             ^C    -   (Control C).  Warm boot.  Same as the standard
                       CP/M or ZCPR2 ^C.

        Entering commands in HSH is similar to doing so in the standard
        command processor, but there are numerous additional editing
        options.  These have been patterned (a bit loosely in a few
        places) after the WordStar editing commands.

             ^A    -   Back one word

             ^D    -   Forward one character.

             ^F    -   Forward one word.

             ^G    -   Delete current character.

             ^H    -   (Backspace).  Delete previous character.

             ^J    -   Display edit command help message and resume
                       editing line.

             ^P    -   Remove any special meaning from the next
                       character.  For example, ^P^H inserts a ^H
                       (backspace) into the line.

             ^Q    -   Back one command.

             ^R    -   Forward one command.

             ^S    -   Back one character without deleting.

             ^T    -   Delete to beginning of next word.

             ^U    -   Delete entire line.









        HSH.DOC    Version 1.1  6 Oct 85                   Page 4


             ^V    -   Insert a character.

             ^W        Delete to beginning of previous word.

             ^Y    -   Delete to end of line.

             ^Z    -   Delete current command.  If the cursor is on a
                       semicolon, the command to the right will be
                       deleted.

        The command will be processed when RETURN or ENTER is pressed.
        The cursor need not be at the end of the line.

        The real power of HSH, however, is in the ability to recall and
        edit previous command lines.  This is controlled by several
        additional command keys:

             ^E    -   Recall previous command line.  Repeated
                       application gets successively earlier command
                       lines.  If there is no previous command line (or
                       it has not been kept in the history), the bell
                       will sound.  The ^U editing command resets the
                       internal pointer to the end so the next ^E gets
                       the last command line executed again.

             ^L    -   Searches for a previous command line which matches
                       the current line to the left of the cursor.  Case
                       is immaterial.  If none is found, the bell will
                       sound.  For example, if the previous command lines
                       were

                                 dir
                                 ws test.doc
                                 type whatever.c
                                 whatever;type what.out
                                 ws what.out
                                 dir

                       then typing "w^L" would recall the command
                       "ws what.out".  The cursor is left after the "w",
                       so typing "^L" again would recall
                       "whatever;type what.out".  If "ws^L" were typed
                       initially, the "whatever" command would be skipped
                       and the two "ws" commands would be recalled.

             ^X    -   Recalls the next command (assuming a previous
                       command has been recalled with ^E and is being
                       edited).  If there is no next command, deletes
                       the current line.

        While the editing commands may seem a bit complex at first, a
        little playing at the terminal will make them very natural and
        easy to use.  The ^L command, in particular, is quite different
        from the commands found in most editors.  With a very little
        practice, command line editing with HSH becomes almost automatic








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        and one soon wonders how one lived without it.



        For the Hacker.

        HSH was written in C and compiled with the Software Toolworks
        C/80 compiler using a private run time library.  Source code is
        included for informational purposes.  It will not be trivial to
        convert to use the standard C/80 library or any other C compiler.
        Anyone interested is welcome to try, but I cannot provide much
        assistance.

        <End of Document>