Shell (Command Prompt)
The A-Shell shell layer, aka the "command prompt" or "dot prompt," functions like the familiar Windows and UNIX shells: it provides an environment with its own set of commands, a scripting capability, and more importantly a launch pad for executing application programs. The most unusual aspects of the A-Shell shell are:
| • | It supports its own virtual DevPPN-style file system structure and syntax that nevertheless maps directly on to the native (Windows or UNIX) file system structure. |
| • | It is transparent, or semi-permeable, in the sense that it offers the ability to see through it to the underlying OS or shell environment, including querying the native environment, scanning native directories, and even executing native programs. You have the choice of operating completely within the shell—for maximum portability between operating systems—or of incorporating features of the native environment—for maximum power and flexibility—without having to recreate them. |
Command Line Editing
In the case of a real terminal connection, when there are no commands or characters queued up, such as in a Command File or via redirection, the shell displays its prompt (typically a single dot; see SET.LIT to change it) and waits for the user to enter a command. In addition to ordinary text, the following special commands are available:
Command |
Single Key |
Action |
|---|---|---|
Ctrl+R |
Page Up |
Cycle backwards through the command line history, one at a time |
Ctrl+T |
Page Down |
Cycle forward through the command line history |
Ctrl+U |
|
Move cursor to beginning of line |
Ctrl+H |
Left Arrow |
Move cursor left, non destructive |
Ctrl+L |
Right Arrow |
Move cursor right, non destructive |
Ctrl+Q |
Insert |
Toggle insert mode |
Ctrl+Z |
|
Erase line |
Ctrl+Y |
|
Erase from cursor to end of line |
Ctrl+A |
|
Move cursor to start of prior word |
Ctrl+W |
|
Move cursor to start of next word |
Ctrl+N |
|
Move cursor to end of line |
Ctrl+F |
|
Insert a space |
Ctrl+D |
Delete |
Delete character under cursor |
|
Backspace |
Move cursor left, destructive |
Note that except for Ctrl+R and Ctrl+T, these commands are identical to those supported by the INFLD field editor (see Keyboard Commands for the complete set) and largely shared with those of the VUE file editor.
See Also
