Glossary
Alias
A name used as an
abbreviation for one or more commands. An alias allows
you to replace any command string with a short sequence
of characters.
Applesoft
An implementation of BASIC for the Apple II.
APW
Apple Programmer's Workshop. Similar to ORCA.
BASIC
Beginners All-purpose Symbolic Instruction Code. A simple computer
language.
Built-in Command
A command processed by gsh. These commands are not
external to the shell, but are included within the
gsh program.
Command
An action for gsh to perform. Commands can be
either simple or compound. A simple command is an alias assignment,
variable assignment, I/O redirection, or built-in
command. A compound command is a pipeline.
Directory
A special
type of file that contains a list of other files; usually
used to categorize files related in some way.
Environment
The state of a process, which includes information such as
its open files, current directory (working directory),
and local and global variables. Three environments exist
under gsh:
Child Environment
The environment of the child process.
Current Environment
The environment of the current process.
Parent Environment
The environment of the parent process.
Environment file
A file that is interpreted by an application to allow the
user to customize its operation. For gsh, this
file is gshrc.
Export
A way to pass a variable from a parent process to child process.
File
An object used
to store data and/or programs. On the IIgs, files
are tagged with types such as EXE, SRC, TXT, and so forth.
Filter
A command
that reads from its standard input and writes to its
standard output. For example, a filter program could be
written to convert all characters to upper case. Filters
are used mainly in pipelines.
Flag
A character
used to represent an option to a command. Flags are
either short or long options whose character
representations are "-" and "+".
Glob
Slang for Pathname Expansion.
GNO/ME
GNO Multitasking Environment. The complete package including
the GNO kernel and the GNO Shell.
GNO Kernel
Heart of GNO/ME. Executes processes when asked by the GNO Shell.
GNO Shell
Provides
an interface between the user and the GNO kernel.
gsh
GNO Implementation of a UNIX-like shell.
GS/OS
16 bit
Operating System for the Apple IIgs.
History
A variable
number of command-lines saved by gsh for future
reference. The number of command-lines saved is dependent
on the HISTORY environment variable.
History file
A file
containing command-lines entered while in a gsh
session. The number of command-lines saved is dependent
on the SAVEHIST environment variable.
Interrupt
A signal
generated by a sequence of keyboard characters or by a
command that terminates the current executing process,
unless the process has set up a trap to handle the
interrupt signal.
I/O Redirection
The
process of changing the standard input, standard output,
and standard error associated with a process so that it
is redirected to a file instead of the console.
Job
A set of related
processes. A job can be either:
Background Job
A process
that executes with the current process. Background jobs
are not associated with the terminal.
Foreground Job
A process
that is currently executing and which is associated with
the terminal.
Multiprocessing
Indicates a machine with more than one CPU.
Multitasking
The ability to run more than one program at a time, or the
illusion of more than one program running at a time;
usually the latter.
ORCA
Shell programing
environment for the Apple //gs. Also a type of whale.
Path Search
The means of searching a pathname list for a command or
script.
Pathname
A string used to identify a file.
Pathname Completion
The means of generating all pathnames matching a given pattern.
Pathname Expansion
The means of replacing a pattern with a list of pathnames
matching that pattern.
Pattern
A string of
characters used to match literal characters and/or
multiple characters.
Permission
Each file
has certain permissions associated with it: destroy,
rename, backup, invisible, write, and read.
Pipe
A conduit
through which a stream of characters can pass from one
process to another. This is accomplished by linking the
standard output of one process to the standard input of a
second process.
Pipeline
Two or more
processes connected together by pipes.
Process
A single
thread of execution that consists of a program and an
execution environment. If a process creates another process,
the creator is known as the parent process;
the created process is known as the child process.
Process ID
Each active process is uniquely identified by a positive
integer called the process id.
ProDOS
8-bit Disk
Operating System for Apple II computers.
Prompt
A message
displayed by gsh when it is ready to receive a
command.
Quoting
A means of
including special characters as arguments to a command or
as the command name. Certain characters have certain
meanings to gsh and quoting them makes
gsh ignore them.
Reserved Word
A word
that is treated specially by gsh. This word is
part of the gsh grammar.
Script
A sequence of
commands contained in a file.
Signal
An asynchronous message that consists of a number or name
that can be sent from one process to another.
Standard Error
The file associated with error messages for a process. This
file is usually the terminal.
Standard Input
The file associated with a processes input. This file is
usually the terminal.
Standard Output
The file associated with a processes output. This file is
usually the terminal.
Tilde Expansion
Words beginning with "~" are treated
specially by gsh. The "~" is
expanded to the value of the HOME environment variable.
UNIX
Popular
operating system which has growing use in education and
business. One of the first operating systems to support
multitasking.
Variable
A named
location in gsh that contains text. The text of a
variable can be expanded in a command by preceding the
variable name with a dollar sign ($).
Wildcard
See Pattern and Pathname Expansion.
Working directory
The current directory.