RUN/EXEC User Commands
NAME
run - Execute Script
exec - Executes commands in batch mode
SYNOPSIS
run SCRIPT PARAMETERS
exec BATCH
DESCRIPTION
JANOS uses a PHP-like language for scripting. In batch file execution,
scripts may be used to render batch file commands which are then
executed. This is analogous to using PHP to render an HTML document
which is then served to a browser. The RUN command executes the script
the results of which are simply sent to the display. In this case
the SCRIPT is essentially a program.
The SCRIPT file typically has a PRG file extension. If an extension is
omitted then .PRG is assumed. The system searches for the SCRIPT file
as it would a Java program. Scripts may be placed in the /flash
folder and easily executed without path or extension using RUN.
Script files accept PARAMETERS as do batch files and Java applications.
The EXEC form of the command simply executes the supplied BATCH file.
This is equivalent to entry of the filename at the command line except
that the BAT file extension is not required.
NOTES
The RUN command can be used to render a batch program allowing you to
examine the resulting commands without executing them. Once you are
satisfied that the script generates the correct command set you can
execute the batch file normally.
A SCRIPT could be written to output information using the ECHO command
allowing it to be used without the RUN command in batch mode.
Scripts are compiled and therefore run fairly efficiently. The resulting
compiled script is cached for the duration of the command session.
The RUN/EXEC command will process a piped command set.
EXAMPLES
Let's take the following script easily created in the /flash/hello.bat
file using the
ED editor. Here we display the script and use
GREP
to enumerate the lines for us.
bruce_dev /> cat /flash/hello.bat | grep -n
1: <?
2: print('@echo "Yo! Hows it goin?"');
3: ?>
bruce_dev />
Here we use the script PRINT command to output a single command line
utilizing ECHO to offer the hello salutation. The '@' in the created
command line instructs the batch processing to not echo the command itself.
We just want to see the greeting.
The script can be simply executed by name.
bruce_dev /> hello
Yo! Hows it goin?
bruce_dev />
We can use RUN to validate the script output without executing it as
follows. This shows you what the script produces without invoking the
batch processor to execute the line.
bruce_dev /> run hello.bat
echo "Yo! Hows it goin?"
bruce_dev />
Although we execute this script by simply entering its name on the command
line we could more explicitly cause it to execute using the EXEC command.
bruce_dev /> exec /flash/hello.bat
Yo! Hows it goin?
bruce_dev />
Now we can see the difference between RUN and EXEC. Here we use RUN to
render the command and then hand that to the batch processor for the same
now familiar result.
bruce_dev /> run hello.bat | exec
Yo! Hows it goin?
bruce_dev />
Just a word about the script. In the program above, line 3 is unnecessary
as the end of file is a suitable termination for a script. Also, in this
case the script performs such a simplistic action that the scripting is
really itself unnecessary. You might imagine, however, that you may want
to create a more complicated procedure like that in the
CKSUMS script.
SEE ALSO
HELP Topics:
BATCH,
SCRIPTING,
PHP,
CKSUMS
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