You can run MEL scripts as separate files. They have the extension .mel by default.
You can execute external script files in two ways:
When you source a MEL script, MEL does not allow you to forward reference locally scoped procedures. Locally scoped procedure definitions must appear before they are called. For example, in a file called noForwardRef.mel, define the local procedures before they are referenced.
proc myLocalProc() {
print "In myLocalProc()\n";
}
proc anotherLocalProc() {
print "In anotherLocalProc()\n";
myLocalProc;
}
global proc noForwardRef() {
print "Calling anotherLocalProc()\n";
anotherLocalProc;
}
If you change a script after sourcing it, the change is not automatically picked up by Maya. You need to re-run the script with File > Source Script.
When you type the name of the file, Maya sources the contents of the file, and if a procedure with the same name exists in the file, Maya executes it. This lets you create scripts that work like built-in commands.