| command (MEL) |
Only available in
MEL |
system
|
In categories: System, Utilities |
Go to: Synopsis. Return value. Related.
MEL examples.
system string
system is NOT undoable, NOT queryable, and NOT
editable.
The string argument is a command which gets executed from the
shell. The output of the executed command is returned as a string.
Note that the system command is system dependent, and will give
different results on Windows than on a UNIX system. Special
Notes: To run a command in the background on Linux, you must
redirect its output. e.g.:
system("sleep 10 >/dev/null
2>&1 &");
Naturally, you can send output to somewhere other than /dev/null if
you like. To run a command in the background on Windows, use either
the "start", "shell", or "load" command. The only difference
between the "start" and "shell" is that "shell" uses the command
processor, so the built-in commands (e.g. DIR, COPY) will be
available.
e.g.:
system("start
C:/aw/Maya/bin/fcheck.exe " + $filename);
"load" is another keyword available on Windows. Using the "load"
keyword followed by a filename causes Windows to attempt to find
the default application for that type of file. The file is then
opened with that application as a background task. If you use the
"start" command, a command process window will pop up in Windows
and the MEL function that system is called from will wait until the
process is complete before continuing. If you are attempting to
hide this pop up window, in some cases you may not want to use the
"shell" command. If you use the "shell" command, the command window
will be hidden and the process will run in the background, but the
MEL function that "system" was called from will continue running,
and will not wait for the process to complete. This may cause
problems if you are relying on the completion of the system
function before continuing on in the calling MEL Script. The
solution is to simply call system with no "start" or "shell" extra
command.
e.g.:
system("C:/aw/Maya/bin/fcheck.exe " +
$filename);
This will run the process silently so a window does not pop up, and
it will also run the process in the foreground, so the calling MEL
Script waits until the process is complete before continuing.
| string |
Result of execution |
exec, pclose,
popen
// On Linux
//
system("/usr/bin/date");
// Result: Tue Nov 23 18:12:39 EST 1999
//
// On Windows
//
system("start C:/WINNT/NOTEPAD.EXE" );
$directoryListing = system("DIR");
// Make a sample file to use as a test example
//
$exampleFileName = ( `internalVar -userTmpDir` + "example.txt" );
$fileId=`fopen $exampleFileName "w"`;
fprint $fileId "Hello there\n";
fclose $fileId;
// Use the "load" keyword to open the file with the default app.
// (Windows only)
//
system("load " + $exampleFileName );