gno/doc/refs.aug96/gsh.3.html
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<p><font size="6" face="Times">Chapter 3</font></p>
<p><font size="6" face="Times">Using the GNO Shell more
productively</font></p>
<p align="right"><font size="2" face="Times">&quot;And then one
day, hooray! Another way for gnomes to say hooray!&quot;</font></p>
<p align="right"><font size="2" face="Times">Syd Barret, The
Gnome</font></p>
<p>&nbsp;</p>
<p><font face="Times"><b></b></font>&nbsp;</p>
<p><font face="Times"><b></b></font>&nbsp;</p>
<p><font face="Times"><b>What does this command do?</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">If you are unfamiliar with what a
particular command actually does or what arguments it accepts,
you can check quickly by using the electronic manual. GNO/ME
includes a utility called <b>man </b>which displays the manual
pages for a command whose name you supply as an argument. The <b>man</b>
utility uses another utility called <b>more</b> to actually
display the pages nicely on the screen. While both of these
utilities have electronic manual entries, we have included the
printed manual pages in the GNO/ME package to get you started.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>Option Arguments</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">As mentioned in Chapter 2 <b>Executing
Commands</b>, arguments are passed to a command to extend its
usefulness. The arguments presented in the last chapter were
words, such as foo, bar and foo.c. Standards exist under unix for
programs to accept command-line option arguments. Option
arguments (as the name suggests) are optional. There are two
standards, short options and long options. Short options are
characters that represent commands, whereas long options contain
the entire option name.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Consider the following output of the </font><font
size="2" face="Courier">CATALOG</font><font face="Times"> command
from ProDOS:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">/DEV</font></p>
<p><font size="2" face="Courier">NAME TYPE BLOCKS MODIFIED
CREATED ENDFILE SUBTYPE</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">FINDER.DATA $C9 1 21-OCT-91
22:38 14-APR-90 18:24 260 </font></p>
<p><font size="2" face="Courier">FINDER.ROOT $C9 1 22-OCT-91
17:12 6-OCT-91 15:40 82 </font></p>
<p><font size="2" face="Courier">GENESYS DIR 1 21-OCT-91 23:37
25-APR-91 15:46 512 </font></p>
<p><font size="2" face="Courier">GSBUG DIR 1 21-OCT-91 23:38
19-JUL-90 16:48 512 </font></p>
<p><font size="2" face="Courier">MERLIN DIR 2 22-OCT-91 2:50
30-APR-91 20:21 1024 </font></p>
<p><font size="2" face="Courier">LIFEGUARD $B3 73 4-SEP-87 4:51
25-DEC-89 20:22 36608 </font></p>
<p><font size="2" face="Courier">ORCA DIR 2 22-OCT-91 17:12
14-SEP-89 18:27 1024 </font></p>
<p><font size="2" face="Courier">GNO DIR 2 22-OCT-91 17:12
13-AUG-91 16:36 1024 </font></p>
<p><font size="2" face="Courier">FAST.ANIM DIR 2 21-OCT-91 23:44
11-MAY-91 10:50 1024 </font></p>
<p><font size="2" face="Courier">MICOL DIR 2 22-OCT-91 3:10
14-JAN-90 2:46 1024 </font></p>
<p><font size="2" face="Courier">SRC DIR 1 21-OCT-91 23:44
7-AUG-91 20:30 512 </font></p>
<p><font size="2" face="Courier">NIFTYLIST.V3.3 DIR 2 21-OCT-91
23:44 29-JUL-91 4:04 1024 </font></p>
<p><font size="2" face="Courier">MCSRC DIR 1 21-OCT-91 23:45
7-AUG-91 20:34 512 </font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">BLOCKS FREE:43923 BLOCKS
USED:21185 TOTAL BLOCKS:65108</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">It is impossible to get any variation in
the format of this output. While the GNO/ME utility <b>ls</b>
serves the same purpose as the command </font><font size="2"
face="Courier">CATALOG</font><font face="Times"> from Applesoft
BASIC, it has a wide number of options which can tailor the
output to specific needs. Here is how <b>ls</b> can be used to
give similar output to the </font><font face="Courier">CATALOG</font><font
face="Times"> command:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1] 2:13am root % <b>ls -l</b></font></p>
<p><font size="2" face="Courier">:dev</font></p>
<p><font size="2" face="Courier">total 45k</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 512 Oct 21
23:45 1991 MCSrc</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 1024 Oct 21
23:44 1991 NiftyList.v3.3</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 1024 Oct 21
23:44 1991 fast.anim</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 512 Oct 21
23:37 1991 genesys</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 1024 Oct 22
17:29 1991 gno</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 512 Oct 21
23:38 1991 gsbug</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 1024 Oct 22
02:50 1991 merlin</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 1024 Oct 22
03:10 1991 micol</font></p>
<p><font size="2" face="Courier">drw--rd 0100 dir 1024 Oct 22
17:28 1991 orca</font></p>
<p><font size="2" face="Courier">drw--rd 0000 dir 512 Oct 21
23:44 1991 src</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The </font><font size="2" face="Courier"><b>-l</b></font><font
face="Times"> short option argument tells <b>ls</b> to format the
output in long format. <b>ls</b> supports only short options. If <b>ls</b>
did support long options, the above command could be changed to <b>ls
+format-long</b>. This is clearly more descriptive of what
function <b>ls</b> will perform. For users to new to the U</font><font
size="2" face="Times">NIX</font><font face="Times"> environment,
long format options are more user-friendly. However, advanced U</font><font
size="2" face="Times">NIX</font><font face="Times"> users prefer
short options because of their brevity.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">As indicated above, <b>ls</b> has a wide
number of options available to format the output. Use the command
&quot;<b>ls -?</b>&quot;<b> </b>to get a short list of these
options. It is left as an exercise for the user to discover how
these options affect the output of <b>ls</b>. For a complete
description of the <b>ls</b> command and its options use the
command <b>man ls</b>.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">As an example of the usage and importance
of long options, the following is the result of the </font><font
size="2" face="Courier">+help</font><font face="Times"> option
given to the <b>coff</b> utility. Note the use of both short and
long options:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">coff [-OPTIONS] filename
[segment..] [loadsegment..]</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">OPTIONS DESCRIPTION</font></p>
<p><font size="2" face="Courier">-v [+version] display coff's
version number</font></p>
<p><font size="2" face="Courier">-D [+default] disable default
options</font></p>
<p><font size="2" face="Courier">-d [+asm] dump segment body in
65816-format disassembly</font></p>
<p><font size="2" face="Courier">-T [+tool] interpret Toolbox,
GS/OS, ProDOS, ROM calls</font></p>
<p><font size="2" face="Courier">-x [+hex] dump segment body in
hex (can be used with '+asm')</font></p>
<p><font size="2" face="Courier">-l [+label] print expressions
using labels (default is offsets)</font></p>
<p><font size="2" face="Courier">-t [+infix] display expressions
in infix form</font></p>
<p><font size="2" face="Courier">-p [+postfix] display
expressions in postfix form (default)</font></p>
<p><font size="2" face="Courier">-m [+merlin] format of '+asm' to
use merlin opcodes (default)</font></p>
<p><font size="2" face="Courier">-o [+orca] format of '+asm' to
use orca/m opcodes</font></p>
<p><font size="2" face="Courier">-a [+shorta] assume 8-bit
accumulator for disassembly</font></p>
<p><font size="2" face="Courier">-i [+shorti] assume 8-bit index
registers for disassembly</font></p>
<p><font size="2" face="Courier">-s [+header] dump segment
headers only</font></p>
<p><font size="2" face="Courier">-n [+noheader] do not print
segment headers</font></p>
<p><font size="2" face="Courier">-f [+nooffset] do not print
offset into file</font></p>
<p><font size="2" face="Courier">-h [+help] print this
information, then quit</font></p>
<p><font size="2" face="Courier">filename name of file to dump</font></p>
<p><font size="2" face="Courier">[segment] names of segments in
file to dump</font></p>
<p><font size="2" face="Courier">[loadsegment] names of load
segments in file to dump</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The long options are much more descriptive,
and provide a very easy way to remember options of programs. If
an option passed to a shell utility program is not understood by
that program, you will generally receive an error message stating
that the option is not understood. If the program is
user-friendly, a brief list of supported options will also be
displayed.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>Entering Multiple commands</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">It is possible to give multiple commands to
the GNO shell for processing. To execute multiple commands, place
a semi-colon, &quot;;&quot;, between them. The commands will be
executed sequentially in the order they are entered on the
command-line. Take care not to exceed the 1024 character
command-line buffer. It is possible to execute multiple commands
at the same time, this feature is discussed in Chapter 3 <b>Background
Execution of Commands</b>.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">To run the <b>echo</b> command and the <b>ls</b>
command in succession, enter the following on the command line:</font></p>
<p><font size="2" face="Courier">% <b>echo Running ls ; ls -l</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The output of the preceeding command will
display the string &quot;</font><font size="2" face="Courier">Running
ls</font><font face="Times">&quot; followed by the output of the
&quot;<b>ls -l</b>&quot; command. This method of running several
commands in succession is used often to save typing.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>Using Aliases as Shorthand</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>gsh</b> provides a built-in command, </font><font
size="2" face="Courier">alias</font><font face="Times">, which
allows any command you would type on the command-line to be
renamed. You are not limited to renaming a single command name.
Rather, you could rename an entire command-line, which could
allow you to use the name &quot;</font><font size="2"
face="Courier">backup</font><font face="Times">&quot; to execute
the command &quot;</font><font size="2" face="Courier">backup
+source /system +destination /tape.drive</font><font face="Times">&quot;.
The </font><font size="2" face="Courier">alias</font><font
face="Times"> command is also a very powerful means of
customizing your GNO environment to emulate other computing
environments.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">To emulate the ORCA environment, the
following aliases could be entered into your <i>gshrc</i> file,
or a script called <i>orca.alias</i> that <i>gshrc</i> would run:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier"><b>alias copy cp</b></font></p>
<p><font size="2" face="Courier"><b>alias cat &quot;ls -l&quot;</b></font></p>
<p><font size="2" face="Courier"><b>alias catalog &quot;ls
-l&quot;</b></font></p>
<p><font size="2" face="Courier"><b>alias move mv</b></font></p>
<p><font size="2" face="Courier"><b>alias rename mv</b></font></p>
<p><font size="2" face="Courier"><b>alias delete rm</b></font></p>
<p><font size="2" face="Courier"><b>alias type cat</b></font></p>
<p><font size="2" face="Courier"><b>alias prefix cd</b></font></p>
<p><font size="2" face="Courier"><b>alias create mkdir</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">If you alias a string containing multiple
words, you must enclose the string in quotes, as done for the
catalog alias.<b> gsh </b>interprets the string as one value. If
you do not include both the opening and closing quotes, the alias
command will notify you of your error.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">You can view any alias' that are set by
entering the </font><font size="2" face="Courier">alias</font><font
face="Times"> command without any arguments. The setting of a
particular alias can be viewed by entering one argument
consisting of the name of the alias to view.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">If you wish to remove an alias, use the
command </font><font size="2" face="Courier">unalias</font><font
face="Times"> with the aliased name as the argument. To remove
the aliases from the </font><font size="2" face="Courier">orca.alias</font><font
face="Times"> file given above, you could do the following:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">% <b>unalias copy cat catalog
move rename delete type prefix create</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Unlike the </font><font size="2"
face="Courier">alias</font><font face="Times"> command, the </font><font
size="2" face="Courier">unalias</font><font face="Times"> command
can take multiple arguments. See Chapter 5 <b>Built-in Commands</b>
for further discussion of the </font><font size="2"
face="Courier">alias</font><font face="Times"> and </font><font
size="2" face="Courier">unalias</font><font face="Times">
commands. </font></p>
<p><font face="Times"><b>Redirecting Input and Output</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Most shell utilities write their output to
the screen. However, under GNO/ME, like ORCA, it is possible to
redirect<b> </b>that output to a file or a GS/OS device. The
output of the <b>ls</b> command above was imported into this
manual by redirecting it to a file. In addition to redirecting
the output of a shell utility, it is also possible to redirect
the input of that utility. Consider the following <b>gsh</b>
session:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1]% <b>echo this is a test</b></font></p>
<p><font size="2" face="Courier">this is a test</font></p>
<p><font size="2" face="Courier">[2]% <b>echo this is a test &gt;
file1</b></font></p>
<p><font size="2" face="Courier">[3]% <b>cat file1</b></font></p>
<p><font size="2" face="Courier">this is a test</font></p>
<p><font size="2" face="Courier">[4]% <b>cat &lt; file1</b></font></p>
<p><font size="2" face="Courier">this is a test</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">In the example above, <b>cat</b> takes
input from <i>standard input</i>. In command 3 above, <b>cat</b>
takes as an argument the filename file1 and writes the contents
of that file to <i>standard output</i>. Where no filename
argument is given, <b>cat</b> reads input from standard input and
writes the output to standard output</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">In the case of command 4 above, <b>cat</b>
contains no arguments and therefore reads from standard input.
However, <b>gsh</b> interprets the &quot;&lt;&quot; redirection
operator and opens the file </font><font size="2" face="Courier">file1</font><font
face="Times"> for use as standard input. Therefore, <b>cat</b>
will take its input from </font><font size="2" face="Courier">file1</font><font
face="Times">, even though it thinks it is reading input from
standard input. This input redirection is transparent to the
utility, making it work with most shell utilities.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Command 2 above created a new file called
file1. If this file had existed prior to the command then it
would have been erased. It is possible to append output to the
end of the file by using the &quot;</font><font size="2"
face="Courier">&gt;&gt;</font><font face="Times">&quot;
redirection operator. Consider the following <b>gsh</b> session:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[5]% <b>echo second line
&gt;&gt; file1</b></font></p>
<p><font size="2" face="Courier">[6]% <b>cat file1</b></font></p>
<p><font size="2" face="Courier">this is a test</font></p>
<p><font size="2" face="Courier">second line</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Output that is sent to <i>standard error</i>,
can also be redirected. The &quot;</font><font size="2"
face="Courier">&gt;&amp;</font><font face="Times">&quot; operator
redirects standard error to a file and &quot;</font><font
size="2" face="Courier">&gt;&gt;&amp;</font><font face="Times">&quot;
appends standard error to the end of the file. Below is a summary
of the redirection operators:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Standard Input Standard Output Standard
Error</font></p>
<p><font size="2" face="Courier">&lt;</font><font face="Times">
Redirect Input from file</font></p>
<p><font size="2" face="Courier">&gt;</font><font face="Times"> </font><font
size="2" face="Courier">&gt;&amp;</font><font face="Times">
Redirect Output to file</font></p>
<p><font size="2" face="Courier">&gt;&gt;</font><font
face="Times"> </font><font size="2" face="Courier">&gt;&gt;&amp;</font><font
face="Times"> Redirect Output to EOF</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Output can be redirected to a storage
device, printer, modem, or any other valid GNO or GS/OS device.
This provides a very powerful means of communicating directly
with these devices from within <b>gsh</b>. One quick and dirty
example of redirection allows a background version of <b>gsh</b>
to be run on a terminal connected directly through the modem
serial port:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1]% <b>gsh &lt; ttya &gt; ttya
&gt;&amp; ttya &amp;</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b></b></font>&nbsp;</p>
<p><font face="Times"><b>Pipelines</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">In addition to the redirection operators,
there is one additional operator which gives control over how
input and output are handled. The operator is a <b>pipeline</b>,
&quot;</font><font size="2" face="Courier">|</font><font
face="Times">&quot;. Pipelines allow the standard output of one
command to be used as the standard input to another command. This
is almost equivalent to running the first command with its output
redirected to a temporary file, then running the second command
with its input redirected from the temporary file, then removing
the temporary file. Pipelines make useful <i>filter</i> processes
where the output of one command can be sent to another command
which filters the output to whatever parameters you give the
second command. As an example, you could display all the
filenames with the character &quot;a&quot; in their name:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1]% <b>echo foo &gt; file1;
echo abc &gt;&gt; file1; echo aabc &gt;&gt; file1</b></font></p>
<p><font size="2" face="Courier">[2]% <b>echo GNO &gt;&gt; file1;
echo standard &gt;&gt; file1; echo oof &gt;&gt; file1</b></font></p>
<p><font size="2" face="Courier">[3]% <b>cat file1</b></font></p>
<p><font size="2" face="Courier">foo</font></p>
<p><font size="2" face="Courier">abc</font></p>
<p><font size="2" face="Courier">aabc</font></p>
<p><font size="2" face="Courier">GNO</font></p>
<p><font size="2" face="Courier">standard</font></p>
<p><font size="2" face="Courier">oof</font></p>
<p><font size="2" face="Courier">[4]% <b>cat file1 | grep 'a'</b></font></p>
<p><font size="2" face="Courier">abc</font></p>
<p><font size="2" face="Courier">aabc</font></p>
<p><font size="2" face="Courier">standard</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Pipelines are useful when you wish to view
lines of text in a file that contain a phrase, or if you want to
connect two programs directly, bypassing intermediate files. It
is also possible to connect multiple commands with multiple
pipelines.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Pipelines are frequently used for paging
output. The <b>coff</b> program mentioned above prints the output
of an OMF disassembly to the screen but does not pause when a key
is pressed. In order to pause the display, the output must be
piped through a paging utility. The ORCA shell requires that you
wait for the entire command to complete execution before the
pipeline is processed. However, GNO/ME executes both commands
concurrently which allows the <b>coff</b> utility to execute
while the paging utility displays the program output. GNO/ME
comes with two page utilities, <b>more</b> and <b>less</b>.
Complete desciptions of <b>coff</b>, <b>more</b>, <b>less</b> can
be found in the electronic manual using the <b>man</b> command.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">c.<b>Background Execution of Commands</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">A major benefit of GNO/ME is <i>multitasking</i>.
Multitasking is a means of running multiple applications at once
(not literally but very close). On the Apple IIGS, GNO/ME
accomplishes pre-emptive multitasking by switching among
applications that are running in the background. Any GNO/ME
utility can be run in the background. Applications running in the
background generally run for the same period of time (GNO/ME
switches between applications 20 times a second).</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">To background a shell utility, place the
&quot;</font><font size="2" face="Courier">&amp;</font><font
face="Times">&quot; character at the end of the command-line. The
GNO shell displays a unique process ID and job number for each
backgrounded command.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">It is possible to use the background
character &quot;</font><font size="2" face="Courier">&amp;</font><font
face="Times">&quot; to separate commands as with the
&quot;;&quot; character. Each command with a following &quot;</font><font
size="2" face="Courier">&amp;</font><font face="Times">&quot; is
executed in the background.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Up to 32 processes can executed
concurrently under the GNO Kernel.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Warning: When you exit the GNO Shell all
processes will be terminated including any you may have running
in the background.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Below is a sample session with background
tasks:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[5] script&gt; <b>ps</b></font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">138 running co 1006 0000 0:00 ps</font></p>
<p><font size="2" face="Courier">[6] script&gt; <b>cmpl +p
script.c keep=script &gt; outputfile &amp;</b></font></p>
<p><font size="2" face="Courier">[1] + 141 Running cmpl +p
script.c keep=script &amp;</font></p>
<p><font size="2" face="Courier">[7] script&gt; <b>ps</b></font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">141 waiting co 1006 0000 0:00
cmpl +p script.c keep=script</font></p>
<p><font size="2" face="Courier">142 ready co 100B 0000 0:00 5/cc</font></p>
<p><font size="2" face="Courier">143 running co 100D 0000 0:00 ps</font></p>
<p><font size="2" face="Courier">[8] script&gt; <b>cmpl +p
script.asm keep=script1 &gt; output2 &amp; ps ; ls -s</b></font></p>
<p><font size="2" face="Courier">[2] - 145 Running cmpl +p
script.asm keep=script1 &amp;</font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">141 waiting co 1006 0000 0:00
cmpl +p script.c keep=script</font></p>
<p><font size="2" face="Courier">144 ready co 100E 0000 0:07
5/linker</font></p>
<p><font size="2" face="Courier">.145 ready co 100D 0000 0:00
cmpl +p script.asm keep=script1</font></p>
<p><font size="2" face="Courier">146 running co 100F 0000 0:00 ps</font></p>
<p><font size="2" face="Courier">147 ready co 1011 0000 0:00
5/asm65816</font></p>
<p><font size="2" face="Courier">3 barf 1 outputfile 6 script.asm
1 script.root</font></p>
<p><font size="2" face="Courier">1 foobar 19 script 3 script.c 36
script.sym</font></p>
<p><font size="2" face="Courier">1 output2 6 script.a 6
script.mac 1 typescript</font></p>
<p><font size="2" face="Courier">[9] script&gt; <b>cp script.asm
script2 &amp;</b></font></p>
<p><font size="2" face="Courier">[3] 150 Running cp script.asm
script2 &amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[2] - Done cmpl +p script.asm
keep=script1 &amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1] + Done cmpl +p script.c
keep=script &amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[3] - Done cp script.asm script2
&amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[10] script&gt; <b>ps</b></font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">151 running co 1006 0000 0:00 ps</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The first command line sends the </font><font
size="2" face="Courier"><b>ps</b></font><font face="Times">
command to the shell. </font><font size="2" face="Courier"><b>ps</b></font><font
face="Times"> lists the processes currently being executed by the
GNO kernel. The processes named <b>gsh</b> and <b>NullProcess</b>
are always present. For a complete description of the </font><font
size="2" face="Courier"><b>ps</b></font><font face="Times"><b> </b>command
see Chapter 4 <b>Kernel Commands</b>.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">When a command is executing in the
background, keyboard input is not sent to it. However, output is
still treated in the same way. If the command sends output to the
standard output or standard error, the screen will become
cluttered. Try this example:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1]% <b>ls -l&amp;</b></font></p>
<p><font size="2" face="Courier">[2]% <b>ls -l</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Both the output of commands #1 and #2 will
be sent to the screen. After command #1 is entered and you begin
typing command #2, you will see the output of the first &quot;</font><font
size="2" face="Courier">ls -l</font><font face="Times">&quot;
command being sent to the screen while you enter command #2.
Utilities which produce output should have their standard output
and standard error redirected to a file when they are executed in
the background. See Chapter 3 <b>Redirecting </b></font></p>
<p><font face="Times"><b>Input and Output</b>.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Executing commands in the background
hinders the performance of the Apple IIGS. This is not too
noticeable when one or two commands are being executed but
performance will degrade more noticably as more commands are
started. The Apple IIGS was not designed as a multitasking
computer so the performance of GNO/ME should be understandable.
If you have an accelerator (such as the Transwarp GS or Zip GS)
installed, performance of multiple tasks will be acceptable.</font></p>
<p><font face="Times"><b></b></font>&nbsp;</p>
<p><font face="Times">Now that command backgrounding and
multitasking have been discussed, some more definitions can be
mentioned. A process is a command which has been submitted to the
shell for execution. <b>Gsh</b> contains a set of special
commands which make dealing with processes much easier. <b>gsh</b>
treats each command entered at the command-line as a <b>job</b>,
where a single job may contain multiple processes. For example:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">% <b>ls</b> {one command, one
process, one job}</font></p>
<p><font size="2" face="Courier">% <b>ls ; ps</b> {two commands,
two processes, two jobs}</font></p>
<p><font size="2" face="Courier">% <b>ls &amp; ps</b> {two
commands, two processes, two jobs}</font></p>
<p><font size="2" face="Courier">% <b>ls | more</b> {two
processes, one job)</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">When a job is run from the shell, it can be
in several modes of operation. Jobs can be in any of three
states: <b>running</b>, <b>stopped</b>, or <b>done</b>. A job can
be executing in either the foreground or the background.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Commands exist to place a job in any mode
of operation. When a job is run directly from a command-line it
is running and it is in the foreground. Since the command-line
cannot be accessed, two special keys have been defined: </font><font
size="2" face="Courier"><b>^C</b></font><font face="Times"> kills
the job and </font><font size="2" face="Courier"><b>^Z</b></font><font
face="Times"> will stop the job. When the job is killed, it is
gone forever, but a stopped job can be restarted. When a job is
stopped, the kernel suspends each of the processes in the job.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Jobs that are running in the background or
have been stopped can be accessed using several built-in
commands. The <b>bg</b> command will place a job in the
background, placing it in the running state if necessary. The <b>fg</b>
command will similarly place a job in the foreground, and the <b>stop</b>
command will stop a backgrounded job. The <b>kill</b> command
will terminate a job.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Each time <b>job control</b> is accessed, a
special job status line is displayed following the command. The
first item on the left in brackets is the job number. Next is a
single character, either a '</font><font size="2" face="Courier">+</font><font
face="Times">', '</font><font size="2" face="Courier">-</font><font
face="Times">', or a blank. The '</font><font size="2"
face="Courier">+</font><font face="Times">' designates the
currently accessed job, the '</font><font size="2" face="Courier">-</font><font
face="Times">' is the previously accessed job, and all other jobs
are not specified. The </font><font size="2" face="Courier">jobs</font><font
face="Times"> command will display a list of all jobs.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">This example was used in Chapter 3 <b>Background
Execution of Commands</b>, but now more of the notation will be
understandable</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[5] script&gt; <b>ps</b></font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">138 running co 1006 0000 0:00 ps</font></p>
<p><font size="2" face="Courier">[6] script&gt; <b>cmpl +p
script.c keep=script &gt; outputfile &amp;</b></font></p>
<p><font size="2" face="Courier">[1] + 141 Running cmpl +p
script.c keep=script &amp;</font></p>
<p><font size="2" face="Courier">[7] script&gt; <b>ps</b></font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">141 waiting co 1006 0000 0:00
cmpl +p script.c keep=script</font></p>
<p><font size="2" face="Courier">142 ready co 100B 0000 0:00 5/cc</font></p>
<p><font size="2" face="Courier">143 running co 100D 0000 0:00 ps</font></p>
<p><font size="2" face="Courier">[8] script&gt; <b>cmpl +p
script.asm keep=script1 &gt; output2 &amp; ps ; ls -s</b></font></p>
<p><font size="2" face="Courier">[2] - 145 Running cmpl +p
script.asm keep=script1 &amp;</font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">141 waiting co 1006 0000 0:00
cmpl +p script.c keep=script</font></p>
<p><font size="2" face="Courier">144 ready co 100E 0000 0:07
5/linker</font></p>
<p><font size="2" face="Courier">.145 ready co 100D 0000 0:00
cmpl +p script.asm keep=script1</font></p>
<p><font size="2" face="Courier">146 running co 100F 0000 0:00 ps</font></p>
<p><font size="2" face="Courier">147 ready co 1011 0000 0:00
5/asm65816</font></p>
<p><font size="2" face="Courier">3 barf 1 outputfile 6 script.asm
1 script.root</font></p>
<p><font size="2" face="Courier">1 foobar 19 script 3 script.c 36
script.sym</font></p>
<p><font size="2" face="Courier">1 output2 6 script.a 6
script.mac 1 typescript</font></p>
<p><font size="2" face="Courier">[9] script&gt; <b>cp script.asm
script2 &amp;</b></font></p>
<p><font size="2" face="Courier">[3] 150 Running cp script.asm
script2 &amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[2] - Done cmpl +p script.asm
keep=script1 &amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1] + Done cmpl +p script.c
keep=script &amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[3] - Done cp script.asm script2
&amp;</font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">[10] script&gt; <b>ps</b></font></p>
<p><font size="2" face="Courier">ID STATE TT MMID UID TIME
COMMAND</font></p>
<p><font size="2" face="Courier">1 ready co 1002 0000 0:45
NullProcess</font></p>
<p><font size="2" face="Courier">2 ready co 1007 0000 0:05 gsh</font></p>
<p><font size="2" face="Courier">151 running co 1006 0000 0:00 ps</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Each of the special commands, bg, fg, stop
and kill, take an argument which specifies the job to perform the
operation on. The argument is either a number specifying the
process id, or a '</font><font size="2" face="Courier">%</font><font
face="Times">' followed by one of the following: '</font><font
size="2" face="Courier">+</font><font face="Times">' or '</font><font
size="2" face="Courier">%</font><font face="Times">' for the
current job, a '</font><font size="2" face="Courier">-</font><font
face="Times">' for the previous job, or a number to specify any
specific job. If nothing follows the '</font><font size="2"
face="Courier">%</font><font face="Times">' or the argument is
missing, then the current job is the default.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1] gno&gt; <b>cat gshrc</b></font></p>
<p><font size="2" face="Courier"></font>&nbsp;</p>
<p><font size="2" face="Courier">###</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier"># GNO 2.0 gshrc file</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier">###</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier"># Initialize our environment</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier">set path=&quot;:right:gno:bin
:right:gno:usr:bin&quot;</font></p>
<p><font size="2" face="Courier">set prompt=&quot;[%h] %S%t%s
%C&gt; &quot;</font></p>
<p><font size="2" face="Courier">set
home=&quot;:right:gno:user:root&quot;</font></p>
<p><font size="2" face="Courier">set term=gnocon</font></p>
<p><font size="2" face="Courier">export path prompt home term</font></p>
<p><font size="2" face="Courier">setenv history=100 savehist=25</font></p>
<p><font size="2" face="Courier">###</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier">#Set up standard prefixes for
utilities.</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier">###</font></p>
<p><font size="2" face="Courier">prefix 2
:software:orca:libraries</font></p>
<p><font size="2" face="Courier">prefix 3 :software:orca</font></p>
<p><font size="2" face="Courier">prefix 4 :software:orca:shell</font></p>
<p><font size="2" face="Courier">prefix 5 :software:or<b>^Z</b></font></p>
<p><font size="2" face="Courier">[1] + Stopped (signal) cat gshrc</font></p>
<p><font size="2" face="Courier">[2] gno&gt; <b>jobs</b></font></p>
<p><font size="2" face="Courier">[1] + Running cat gshrc</font></p>
<p><font size="2" face="Courier">[3] gno&gt; <b>bg </b>{output
was not redirected, so screen gets cluttered}</font></p>
<p><font size="2" face="Courier">[1] + Running cat gshrc</font></p>
<p><font size="2" face="Courier">ca:languages</font></p>
<p><font size="2" face="Courier">prefix 6
:software:orca:utilities</font></p>
<p><font size="2" face="Courier">prefix 7 :tmp</font></p>
<p><font size="2" face="Courier">###</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier"># Set up prefixes for
Orca2.0(tm)'s benefit</font></p>
<p><font size="2" face="Courier">#</font></p>
<p><font size="2" face="Courier">###</font></p>
<p><font size="2" face="Courier">prefix 13
:software:orca:libraries</font></p>
<p><font size="2" face="Courier">prefix 14 :software:orca</font></p>
<p><font size="2" face="Courier">prefix 15 :software:or</font></p>
<p><font size="2" face="Courier">[4] gno&gt; <b>stop </b>{Incredibly
fast typing :-) }</font></p>
<p><font size="2" face="Courier">[1] + Stopped (signal) cat gshrc</font></p>
<p><font size="2" face="Courier">[5] gno&gt; <b>jobs</b></font></p>
<p><font size="2" face="Courier">[1] + Running cat gshrc</font></p>
<p><font size="2" face="Courier">[6] gno&gt; <b>fg</b></font></p>
<p><font size="2" face="Courier">[1] + Running cat gshrc</font></p>
<p><font size="2" face="Courier">ca:shell</font></p>
<p><font size="2" face="Courier">prefix 16
:software:orca:languages</font></p>
<p><font size="2" face="Courier">prefix 17
:software:orca:utilities</font></p>
<p><font size="2" face="Courier">alias ls 'ls -CF'</font></p>
<p><font size="2" face="Courier">alias dir 'ls -al'</font></p>
<p><font size="2" face="Courier">alias cp 'cp -i'</font></p>
<p><font size="2" face="Courier">alias rm 'cp -p rm'</font></p>
<p><font size="2" face="Courier">alias mv 'cp -p mv'</font></p>
<p><font size="2" face="Courier">setenv usr<b>^Z</b></font></p>
<p><font size="2" face="Courier">[1] + Stopped (signal) cat gshrc</font></p>
<p><font size="2" face="Courier">[7] gno&gt; <b>jobs</b></font></p>
<p><font size="2" face="Courier">[1] + Running cat gshrc</font></p>
<p><font size="2" face="Courier">[8] gno&gt; <b>kill %1</b></font></p>
<p><font size="2" face="Courier">[9] gno&gt; <b>jobs</b></font></p>
<p><font size="2" face="Courier">[10] gno&gt;</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">There is one additional way that a job may
be stopped. If the job is placed in the background and it
attempts to read from the console, the job will be stopped, and
the status line says &quot;</font><font size="2" face="Courier">(tty
input)</font><font face="Times">&quot; as the reason for the job
being stopped. The job should be foregrounded so that the user
may enter input to the program. It can then be placed back in the
background as necessary (with </font><font size="2"
face="Courier">^Z</font><font face="Times"> and </font><font
size="2" face="Courier">bg</font><font face="Times">).</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>Working with Pathnames</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">To move easily to directories descended
from the home directory, <b>gsh</b> provides the &quot;</font><font
size="2" face="Courier"><b>~</b></font><font face="Times">&quot;
(tilde) character. This character represents the home directory.
Therefore, if your home directory was &quot;</font><font size="2"
face="Courier">:hard:gno:user:root</font><font face="Times">&quot;,
you could use the command &quot;</font><font size="2"
face="Courier"><b>cd ~</b></font><font face="Times">&quot; to
move to the home directory (note that </font><font size="2"
face="Courier">cd</font><font face="Times"> without any arguments
also defaults to the home directory). To move to subdirectories
of the home directory, you could use the command &quot;</font><font
size="2" face="Courier"><b>cd ~/dir1</b></font><font face="Times">&quot;
command. The tilde character is recognized by <b>gsh</b> before
the command is interpreted.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Another special sequence &quot;</font><font
size="2" face="Courier"><b>..</b></font><font face="Times">&quot;,
when used as part of a pathname, will strip the last path between
pathname seperators. For example, the pathname
&quot;/dev/gno/..&quot; would be expanded to &quot;</font><font
size="2" face="Courier">/dev</font><font face="Times">&quot;. The
&quot;</font><font size="2" face="Courier">/gno</font><font
face="Times">&quot; path is stripped as it is before the periods.
This provides an excellent way to backup into your directories.
&quot;Backing up&quot; is limited by the volume directory of the
device being used. </font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Additionally, the character &quot;</font><font
size="2" face="Courier"><b>.</b></font><font face="Times">&quot;,
can be used to signify the current directory.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Examples:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[/dev/gno]% <b>cd ~ </b></font><font
size="2" face="Times">{ change to home directory }</font></p>
<p><font size="2" face="Courier">[/dev/gno]% <b>cd ~/src</b></font></p>
<p><font size="2" face="Courier">[/dev/gno/src]% <b>cp ~/file1
file2 </b></font><font size="2" face="Times">{ copy
/dev/gno/file1 to /dev/gno/src/file2 }</font></p>
<p><font size="2" face="Courier">[/dev/gno/src]% <b>echo ~/..</b></font></p>
<p><font size="2" face="Courier">/dev/gno/..</font></p>
<p><font size="2" face="Courier">[/dev/gno/src]% <b>cd ~/..</b></font></p>
<p><font size="2" face="Courier">[/dev]% <b>mkdir ~/utilities </b></font><font
size="2" face="Times">{ create directory /dev/gno/utilities }</font></p>
<p><font size="2" face="Courier">[/dev]% <b>mkdir ./libraries</b></font><font
size="2" face="Times"> { create directory /dev/libraries }</font></p>
<p><font size="2" face="Courier">[/dev]% <b>cd ~</b></font></p>
<p><font size="2" face="Courier">[/dev/gno]% <b>cp src/file1</b> <b>.</b>
</font><font size="2" face="Times">{ copy /dev/gno/src/file1 to
/dev/gno/file1 }</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Many utilities supplied with <b>gsh</b>
take, as an argument, a filename or filenames. The shell
utilities <b>cat</b>, <b>ls</b>, <b>grep</b>, and <b>cp</b> can
take multiple filenames as arguments. If you wish to invoke any
of these utilities on filenames that have a sequence of
characters in common (ie. </font><font size="2" face="Courier">AND</font><font
face="Times">, </font><font size="2" face="Courier">APPLE</font><font
face="Times">, </font><font size="2" face="Courier">SHK</font><font
face="Times">, </font><font size="2" face="Courier">TXT</font><font
face="Times">, </font><font size="2" face="Courier">FILE2</font><font
face="Times">, </font><font size="2" face="Courier">FILE3</font><font
face="Times">, etc.), <b>gsh</b> provides special characters,
called regular expressions or wildcards, which match multiple
filenames without having to enter all filename arguments
manually.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier"><b>*</b></font><font
face="Times"> Matches any string of characters.</font></p>
<p><font size="2" face="Courier"><b>?</b></font><font
face="Times"> Matches a single character.</font></p>
<p><font size="2" face="Courier"><b>[</b>abc<b>]</b></font><font
face="Times"> Matches any of the characters enclosed in brackets.</font></p>
<p><font size="2" face="Courier"><b>[^</b>abc<b>]</b></font><font
face="Times"> Matches any of the characters not enclosed in
brackets.</font></p>
<p><font size="2" face="Courier"><b>[</b>a<b>-</b>c<b>]</b></font><font
face="Times"> Matches the ascending sequence of characters
enclosed in brackets.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">This method of matching filenames is known
as <b>globbing</b>. <b>gsh</b> performs globbing on the word
prior to executing the command. The following <b>gsh</b> session
illustrates file globbing:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1]% <b>cd /dev/gno/utilities</b></font></p>
<p><font size="2" face="Courier">[2]% <b>ls</b></font></p>
<p><font size="2" face="Courier">:dev:gno:utilities</font></p>
<p><font size="2" face="Courier">CONV Crunch CrunchIIGS DeRez
DiskCheck</font></p>
<p><font size="2" face="Courier">DumpObj Duplicate EMACS Equal
Express</font></p>
<p><font size="2" face="Courier">Files LinkIIGS MakeBin
MakeDirect OrcaDumpIIGS</font></p>
<p><font size="2" face="Courier">Prizm ResEqual Search canon
choose</font></p>
<p><font size="2" face="Courier">clrff cmdfix coff compact count</font></p>
<p><font size="2" face="Courier">detab dir dirff dumpfile eject</font></p>
<p><font size="2" face="Courier">emacs.doc emacs.hlp emacs.rc
emacs.tut help</font></p>
<p><font size="2" face="Courier">init join link macgen makelib</font></p>
<p><font size="2" face="Courier">mem online pageeject pause pwd</font></p>
<p><font size="2" face="Courier">src </font></p>
<p><font size="2" face="Courier">[3]% <b>ls e*</b></font></p>
<p><font size="2" face="Courier">:dev:gno:utilities</font></p>
<p><font size="2" face="Courier">EMACS Equal Express eject
emacs.doc </font></p>
<p><font size="2" face="Courier">emacs.hlp emacs.rc emacs.tut</font></p>
<p><font size="2" face="Courier">[4]% <b>echo *r *m</b></font></p>
<p><font size="2" face="Courier">dir Prizm mem</font></p>
<p><font size="2" face="Courier">[5]% <b>echo *i*</b></font></p>
<p><font size="2" face="Courier">cmdfix CrunchIIGS Prizm
DiskCheck Duplicate Files init join LinkIIGS makelib</font></p>
<p><font size="2" face="Courier">MakeBin MakeDirect link dirff
dumpfile online OrcaDumpIIGS dir</font></p>
<p><font size="2" face="Courier">[6]% <b>echo NoMatch*</b></font></p>
<p><font size="2" face="Courier">No match.</font></p>
<p><font size="2" face="Courier">[7]% <b>echo [a-f]*</b></font></p>
<p><font size="2" face="Courier">coff canon cmdfix compact Crunch
CrunchIIGS DeRez DiskCheck DumpObj Duplicate</font></p>
<p><font size="2" face="Courier">EMACS emacs.doc emacs.hlp
emacs.rc emacs.tut Equal Express Files choose clrff</font></p>
<p><font size="2" face="Courier">count detab CONV dirff dumpfile
eject dir</font></p>
<p><font size="2" face="Courier">[8]% <b>echo [a-fs-t]*</b></font></p>
<p><font size="2" face="Courier">coff canon cmdfix compact Crunch
CrunchIIGS DeRez DiskCheck DumpObj Duplicate</font></p>
<p><font size="2" face="Courier">EMACS emacs.doc emacs.hlp
emacs.rc emacs.tut Equal Express Files choose clrff</font></p>
<p><font size="2" face="Courier">count detab Search src CONV
dirff dumpfile eject dir</font></p>
<p><font size="2" face="Courier">[9]% <b>echo emacs?*</b></font></p>
<p><font size="2" face="Courier">EMACS emacs.doc emacs.hlp
emacs.rc emacs.tut</font></p>
<p><font size="2" face="Courier">[10]% <b>echo [^a-f]*</b></font></p>
<p><font size="2" face="Courier">Prizm help init join LinkIIGS
makelib MakeBin MakeDirect link mem ResEqual</font></p>
<p><font size="2" face="Courier">Search src online pageeject
pause OrcaDumpIIGS pwd macgen</font></p>
<p><font size="2" face="Courier">[11]% <b>echo [^a-fs-t]*</b></font></p>
<p><font size="2" face="Courier">Prizm help init join LinkIIGS
makelib MakeBin MakeDirect link mem ResEqual</font></p>
<p><font size="2" face="Courier">online pageeject pause
OrcaDumpIIGS pwd macgen</font></p>
<p><font size="2" face="Courier">[12]% <b>echo ???</b></font></p>
<p><font size="2" face="Courier">mem src pwd dir</font></p>
<p><font size="2" face="Courier">[13]% <b>echo ?</b></font></p>
<p><font size="2" face="Courier">No match.</font></p>
<p><font size="2" face="Courier">[14]% <b>echo &quot;???&quot;</b></font></p>
<p><font size="2" face="Courier">???</font></p>
<p><font size="2" face="Courier">[15]% <b>do you have a light?</b></font></p>
<p><font size="2" face="Courier">No match.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">As can be seen by the above example,
character matches are case insensitive. The ProDOS file system
treats the filenames &quot;</font><font size="2" face="Courier">file</font><font
face="Times">&quot; and &quot;</font><font size="2"
face="Courier">FILE</font><font face="Times">&quot; as the same
file. <b>gsh</b> recognizes this and does not detract from the
underlying file system.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">File globbing makes passing arguments to
commands much easier and much more powerful. You could easily use
&quot;</font><font size="2" face="Courier">*.c</font><font
face="Times">&quot; as an argument in a number of ways:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">[1]% <b>ls *.C</b></font></p>
<p><font size="2" face="Courier"><b>... </b></font><font size="2"
face="Times">{ lists all filenames ending in &quot;.C&quot; }</font></p>
<p><font size="2" face="Courier">[2]% <b>cc *.C</b></font></p>
<p><font size="2" face="Courier"><b>... </b></font><font size="2"
face="Times">{ compiles all files ending in &quot;.C&quot; }</font></p>
<p><font size="2" face="Courier">[3]% <b>more *.C</b></font></p>
<p><font size="2" face="Courier"><b>... </b></font><font size="2"
face="Times">{ displays contents of all files ending in
&quot;.C&quot; }</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>Quoting Special Characters</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">Beginning with Apple II</font><font
size="2" face="Times">GS</font><font face="Times"> System
Software 6.0, GS/OS is able to read files from Macintosh
computers. The Macintosh uses a filesystem known as HFS, which
allows filenames to contain any character except the colon
(&quot;</font><font size="2" face="Courier">:</font><font
face="Times">&quot;). Because a filename such as
&quot;emacs?*&quot; is valid under HFS, care must be taken or
unexpected results will occur. The word &quot;emacs?*&quot; was
used as a regular expression above to specify a list of filenames
beginning with the word &quot;emacs&quot; and one or more
trailing characters. <b>gsh</b> does provide a way to pass an
argument which contains special shell characters to a command.
This is known as quoting an argument. There are three different
ways to quote an expression:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The single quote will quote everything
between the single quote marks. Thus, to display the contents of
a file on an HFS volume named &quot;emacs?*&quot;:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">% <b>more 'emacs?*'</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The double quote will quote everything
between the double quote marks except variables. See Chapter 5
for more on variables.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">% <b>echo &quot;emacs?*
$home&quot;</b></font></p>
<p><font size="2" face="Courier">emacs?* /dev/gno</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The backslash is used to quote one
character. To pass &quot;</font><font size="2" face="Courier">emacs?*</font><font
face="Times">&quot; as a regular expression using the backslash,
enter the following:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">% <b>ls emacs\?\*</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">One additional purpose of the quoting
mechanism built into <b>gsh</b> is to add spaces to command
arguments. Each command and its arguments is separated by a
space. Multiple spaces between arguments are treated as one
space. Thus, consider the following:</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">% <b>echo a b c</b></font></p>
<p><font size="2" face="Courier">a b c</font></p>
<p><font size="2" face="Courier">% <b>echo 'a b c'</b></font></p>
<p><font size="2" face="Courier">a b c</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>How gsh Finds a Command</b></font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b>gsh</b> has a special variable, </font><font
size="2" face="Courier">PATH</font><font face="Times">, which
specifies the directories and order of directories to search for
shell utilities. This variable is often setup in the <i>gshrc</i>
file although it can be changed as often as needed. The purpose
of the </font><font size="2" face="Courier">PATH</font><font
face="Times"> variable was discussed in Chapter 1 <b>Customizing
the Shell Environment</b>.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">When <b>gsh</b> starts up, it searches all
directories specified in the </font><font size="2" face="Courier">PATH</font><font
face="Times"> variable and establishes a table of all commands,
called a hash table. Because of this table, <b>gsh</b>
&quot;knows&quot; where a command is and can execute the command
much faster than searching through all directories every time the
command is entered.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The search process begins with alias names.
See Chapter 3 <b>Using aliases as shorthand</b>. If an alias is
found that matches the command, the alias is replaced with its
value and the command-line is again parsed. If it was not an
alias, <b>gsh</b> checks to see if it was a special built-in
utility. The search process then searches for the name in the
hash table. If an entry is found in the hash table, the path name
of the command is retrieved and the command is executed. If an
entry is not found, the current path is searched. If the command
name is not found, an error results.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">When the </font><font size="2"
face="Courier">PATH</font><font face="Times"> variable is
changed, <b>gsh</b> does not automatically recreate the command
hash table. You need to issue the command </font><font size="2"
face="Courier"><b>rehash</b></font><font face="Times"> to
recreate the hash table. The more pathnames specified, the
greater the delay in starting <b>gsh</b> and in invoking the </font><font
size="2" face="Courier">rehash</font><font face="Times"> command.
The following shell script changes </font><font size="2"
face="Courier">PATH</font><font face="Times"> and invokes the
rehash command in one step.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">echo Resetting PATH variable
$PATH to $1</font></p>
<p><font size="2" face="Courier">set path=$1</font></p>
<p><font size="2" face="Courier">rehash</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times">The </font><font size="2" face="Courier">$1</font><font
face="Times"> variable will be expanded with the first argument
passed to the script. </font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font size="2" face="Courier">rehash</font><font face="Times">
should also be used if a new utility is copied to one of the
directories specified in the PATH variable. Of course, it is
possible to specify the absolute pathname of any command, but
this is undesirable if the command is frequently used.</font></p>
<p><font face="Times"></font>&nbsp;</p>
<p><font face="Times"><b></b></font>&nbsp;</p>
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