Computer operating systems are among the most complex objects created by mankind... -- Douglas Comer, Operating System Design, the XINU Approach

The GNO shell is an integral part of the GNO Multitasking Environment (GNO/ME). The GNO shell provides the interface between the user and the GNO Kernel. While both work together, the jobs they perform are quite different. This manual documents the functions of the shell. The user interacts with the shell through a command-line interface. Command-line interfaces provide a unique way of interacting with the operating system. Unlike GUIs (Graphical User Interfaces), with which you are already familiar with by using programs such as the Finder and ShrinkIt! GS, all commands are typically entered using the keyboard. The shell interprets commands and passes them to the kernel for control and execution. The command-line interface will be unfamiliar to some people However, once the command-line interface has been mastered, the user should have no difficulty using any current or future GNO applications. Those of you already familiar with Unix interfaces, such as the C shell, Bourne shell, and Korn shell, or the ORCA shell on the Apple IIGS, will begin to realize the advantages which GNO/ME is able to provide. The way this manual is presented allows the complete beginner to simply work through the chapters in a chronological prder. familiarises the user with entering basic commands whereas the more powerful GNO/ME features are introduced in . documents the commands which are built into the GNO Shell and explains shell variables which give the user control over how their installation functions.

When gsh, the implementation of the GNO Shell, is executed, it reads in and processes the gshrc file. This file contains start-up instructions for the shell, which can be used to customize the operation of the shell and other aspects of the system. It is created by the GNO Installer during the installation process. The following is a sample gshrc file (line numbers have been added for convenience): 1 ### 2 # 3 # GNO 2.0 gshrc file 4 # 5 ### 6 # 7 # Initialize our environment 8 # 9 set path=":hard:gno:bin :hard:gno:usr:bin" 10 set prompt="[%h] %S%t%s %C> " 11 set home=":hard:gno:user:root" 12 set term=gnocon 13 export path prompt home term 14 setenv history=100 savehist=25 15 ### 16 # 17 #Set up standard prefixes for utilities. 18 # 19 ### 20 prefix 2 :software:orca:libraries 21 prefix 3 :software:orca 22 prefix 4 :software:orca:shell 23 prefix 5 :software:orca:languages 24 prefix 6 :software:orca:utilities 25 prefix 7 :tmp 26 ### 27 # 28 # Set up prefixes for Orca2.0(tm)'s benefit 29 # 30 ### 31 prefix 13 :software:orca:libraries 32 prefix 14 :software:orca 33 prefix 15 :software:orca:shell 34 prefix 16 :software:orca:languages 35 prefix 17 :software:orca:utilities 36 alias ls 'ls -CF' 37 alias dir 'ls -al' 38 alias cp 'cp -i' 39 alias rm 'cp -p rm' 40 alias mv 'cp -p mv' 41 setenv usrman='/usr/man' 42 set fignore='.a .root .sym' 43 alias zcat 'compress -cd' 44 setenv pager=less 45 setenv less=-e 46 set nonewline=1 47 # 48 # Move to home directory 49 # 50 cd When you install GNO/ME, the GNO installer knows where to find the GNO utilities and any ORCA utilities you may have. Unfortunately it does not know where all the other utilities and applications that you may wish to use are located. It is therefore necessary to edit the setup file in order to tell the GNO shell where these programs are on your hard disk. The setup file, gshrc, is located in the /usr directory of the path where you installed GNO/ME. You can use any text editor from the desktop to edit the gshrc file, or if you are already familiar with the editor vi you can use this utility after launching the GNO kernel. Line 9 is the statement that we are concerned with. Hard represents the name of your particular hard drive volume where you have installed GNO/ME. 9 set path=":hard:gno:bin :hard:gno:usr:bin" You will see that spaces have been inserted between pathnames. The space is the pathname separator and the colon has been used as the path delimiter for this specific variable, PATH. As an exercise, add your system directory to this statement. Line 9 should now look like this: 9 set path=":hard:gno:bin:hard:gno:usr:bin :hard:system" What you have just done allows the GNO shell to find the Finder application. Now go ahead and add any pathnames that hold utilities or applications that you will use frequently from GNO/ME. It should also be noted that it is possible to have more than one pathname containing EXE, SYS16, or EXEC files; this is impossible under ORCA. The PATH variable is discussed thoroughly in . For now, the remaining lines of the gshrc file do not need editing. As you gain an understanding of the system you may wish to make further changes to the gshrc file. Make sure you save the file before you exit the editor. It is possible to modify these instructions while the GNO shell is active, but any changes will be lost upon exiting gsh. If you wish the changes to remain effective for the next session you must add them to the gshrc file. By customizing the gshrc file it is possible to make the GNO environment more like UNIX, the ORCA environment, or something completly different. Customization of the GNO environment leads to greater user productivity.

GNO/ME can be launched from a program launcher, such as the System 6.0 Finder. Launch the GNO Kernel program, kern by double clicking on it. The GNO kernel automatically executes the supplied GNO shell, gsh. The prompt, gsh# indicates that gsh is ready to receive input from the keyboard. To start a new gsh from the command-line simply type gsh. If multiple copies of the gsh process are undesirable, use the command source gsh instead. This is useful for testing changes made to the gshrc file. source is a built-in comand which is discussed in .