gno/doc/refs/gsh/start.docbook

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;; $Id: start.docbook,v 1.1 2012/08/25 07:19:03 gdr Exp $
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<chapter id="gsh-start">
<title>Getting Started with the GNO Shell</title>

<para><quote><emphasis>
Computer operating systems are among the most complex objects created by
mankind...
</emphasis>
</quote>
-- Douglas Comer, Operating System Design, the XINU Approach
</para>

<section>
<title>Introduction</title>

<para>
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.
</para>

<para>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.</para>

<para>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.</para>

<para>The way this manual is presented allows the
complete beginner to simply work through the chapters in a
chronological prder. 
<xref linkend="gsh-interact"/>
familiarises the user with
entering basic commands whereas the more powerful GNO/ME features
are introduced in 
<xref linkend="gsh-productive"/>.
<xref linkend="gsh-commands"/>
documents the commands which are built into the GNO Shell and 
<xref linkend="gsh-shellvars"/>
explains shell
variables which give the user control over how their installation
functions.</para>

</section>
<section id="gsh-start-custom">
<title>Customizing the Shell Environment</title>

<para>When <command>gsh</command>, the implementation of the
GNO Shell, is executed, it reads in and processes the <filename>gshrc</filename>
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.
</para>

<para>
The following is a sample <filename>gshrc</filename> file
(line numbers have been added for convenience):
</para>

<informalexample>
<screen>
1	###
2	#
3	# GNO 2.0 gshrc file
4	#
5	###
6	#
7	# Initialize our environment
8	#
9	set path=&quot;:hard:gno:bin :hard:gno:usr:bin&quot;
10	set prompt=&quot;[%h] %S%t%s %C&gt; &quot;
11	set home=&quot;:hard:gno:user:root&quot;
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
</screen>
</informalexample>

<para>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.</para>

<para>The setup file, <filename>gshrc</filename>, 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 <filename>gshrc</filename>
file, or if you are already familiar with the editor vi
you can use this utility after launching the GNO kernel.</para>

<para>Line 9 is the statement that we are
concerned with. <userinput>Hard</userinput> represents the name of your
particular hard drive volume where you have installed GNO/ME.</para>

<screen>
9	set path=":hard:gno:bin :hard:gno:usr:bin"
</screen>

<para>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:</para>

<screen>
9	set path=":hard:gno:bin:hard:gno:usr:bin :hard:system"
</screen>

<para>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 
<xref linkend="gsh-shellvars"/>.
</para>

<para>For now, the remaining lines of the <filename>gshrc</filename>
file do not need editing. As you gain an understanding of the
system you may wish to make further changes to the <filename>gshrc</filename>
file. Make sure you save the file before you exit the editor.</para>

<para>It is possible to modify these instructions
while the GNO shell is active, but any changes will be lost upon
exiting <command>gsh</command>. If you wish the changes to remain effective
for the next session you must add them to the <filename>gshrc</filename> file.</para>

<para>By customizing the <filename>gshrc</filename> 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.</para>

</section>

<section>
<title>Invoking gsh</title>

<para>GNO/ME can be launched from a program
launcher, such as the System 6.0 Finder. Launch the GNO Kernel
program, <command>kern</command> by double clicking on it. The GNO kernel
automatically executes the supplied GNO shell, <command>gsh</command>.
</para>

<para>The prompt,
<quote>gsh# </quote>
indicates that <command>gsh</command> is ready to receive input from the
keyboard.</para>

<para>To start a new <command>gsh</command> from the
command-line simply type <command>gsh</command>.
If multiple copies of the <command>gsh</command>
process are undesirable, use the command <command>source gsh</command>
instead. This is useful for testing changes made to the
<filename>gshrc</filename> file. 
<command>source</command> is a built-in comand which is discussed in
<xref linkend="gsh-commands"/>.
</para>

</section>
</chapter>