01-18-2007
I don't really understand this question. But let's say you have a process running that is a shell. A user has entered the command "date". So no wthe shell would like to run the separate program called "date" and display the results to the user. So the shell will fork and exec the date program. Why? Because that is the only game in town. There is no other way for it to run another program. Either it can fork/exec and thus run the program or it can tell the user "sorry I don't know how to run programs".
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LEARN ABOUT OPENDARWIN
shell
shell(1F) FMLI Commands shell(1F)
NAME
shell - run a command using shell
SYNOPSIS
shell command [command] ...
DESCRIPTION
The shell function concatenate its arguments, separating each by a space, and passes this string to the shell ($SHELL if set, otherwise
/usr/bin/sh).
EXAMPLES
Example 1: A sample output of shell command.
Since the Form and Menu Language does not directly support background processing, the shell function can be used instead.
`shell "build prog > /dev/null &"`
If you want the user to continue to be able to interact with the application while the background job is running, the output of an exe-
cutable run by shell in the background must be redirected: to a file if you want to save the output, or to /dev/null if you don't want to
save it (or if there is no output), otherwise your application may appear to be hung until the background job finishes processing.
shell can also be used to execute a command that has the same name as an FMLI built-in function.
NOTES
The arguments to shell will be concatenate using spaces, which may or may not do what is expected. The variables set in local environments
will not be expanded by the shell because "local" means "local to the current process."
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO
sh(1), attributes(5)
SunOS 5.10 5 Jul 1990 shell(1F)