<refentry id="shell">
<refnamediv>
<refname>SHELL</refname>
<refpurpose>OS-9 Command Interpreter</refpurpose>
</refnamediv>

<refsynopsisdiv>
<cmdsynopsis>
<command>SHELL</command>
<arg choice="plain">&replstart;arglist&replend;</arg>
</cmdsynopsis>
</refsynopsisdiv>

<refsect1><title>Description</title>
<para>
The Shell is OS-9's command interpreter program. It reads data from
its standard input path (the keyboard or a file), and interprets the
data as a sequence of commands. - The basic function of the shell is
to initiate and control execution of other OS-9 programs.
</para>
<para>
The shell reads and interprets one text line at a time from the
standard input path. After interpretation of each line it reads
another until an end-of-file condition occurs, at which time it
terminates itself. A special case is when the shell is called from
another program, in which case it will take the parameter area (rest
of the command line) as its first line of input. If this command
line consists of &quot;built in&quot; commands only, more lines will be read
and processed; otherwise control will return to the calling program
after the single command line is processed.
</para>
<para>
The rest of this description is a technical specification of the
shell syntax. Use of the Shell is described fully in Chapters 2
and 4 of this manual.
</para>
</refsect1>
<refsect1><title>Shell Input Line Formal Syntax</title>
<synopsis>
&replstart;pgm line&replend; := &replstart;pgm&replend; {&replstart;pgm&replend;}
&replstart;pgm&replend; := [&replstart;params&replend;] [ &replstart;name&replend; [&replstart;modif&replend;] [&replstart;pgm params&replend;] [&replstart;modif&replend;] ] [&replstart;sep&replend;]

Program Specifications

&replstart;name&replend; := &replstart;module name&replend;
           := &replstart;pathlist&replend;
           := ( &replstart;pgm list&replend; )

Parameters

&replstart;params&replend;:= &replstart;param&replend; { &replstart;delim&replend; &replstart;param&replend; }
&replstart;delim&replend; := space or comma characters
&replstart;param&replend; := ex &replstart;name&replend; [&replstart;modif&replend;] chain to program specified
         := chd &replstart;pathlist&replend;    change working directory
         := kill &replstart;procID&replend;     send abort signal to process
         := setpr&replstart;procID&replend; &replstart;pty&replend; change process priority
         := chx &replstart;pathlist&replend;    change execution directory
         := w                                   wait for any process to die
         := p                                   turn &quot;OS9:&quot; prompting on
         := -p                                  turn prompting off
         := t                                   echo input lines to std output
         := -t                                  don't echo input lines
         := -x                                  dont abort on error
         := x                                   abort on error
         := * &replstart;text&replend;          comment line: not processed
&replstart;sep&replend;   := ;     sequential execution separator
         := &amp;     concurrent execution separator
         := !     pipeline separator
         := &replstart;cr&replend; end-of-line (sequential execution separator)


Modifiers

&replstart;modif&replend; := &replstart;mod&replend; { &replstart;delim&replend; &replstart;mod&replend; }
&replstart;mod&replend;   := &lt; &replstart;pathlist&replend; redirect standard input
        := &gt; &replstart;pathlist&replend; redirect standard output
        := &gt;&gt; &replstart;pathlist&replend; redirect standard error output
        := # &replstart;integer&replend; set process memory size in pages
        := # &replstart;integer&replend; K   set program memory size in 1K increments
</synopsis>
</refsect1>
</refentry>