PHP exec – check if enabled or disabled
This will check if the function actually works (permissions, rights, etc): if(@exec(‘echo EXEC’) == ‘EXEC’){ echo ‘exec works’; }
exec
How to get local variables updated, when using the `exec` call?
This issue is somewhat discussed in the Python3 bug list. Ultimately, to get this behavior, you need to do: def foo(): ldict = {} exec(“a=3”,globals(),ldict) a = ldict[‘a’] print(a) And if you check the Python3 documentation on exec, you’ll see the following note: The default locals act as described for function locals() below: modifications to … Read more
Dynamic/runtime method creation (code generation) in Python
Based on Theran’s code, but extending it to methods on classes: class Dynamo(object): pass def add_dynamo(cls,i): def innerdynamo(self): print “in dynamo %d” % i innerdynamo.__doc__ = “docstring for dynamo%d” % i innerdynamo.__name__ = “dynamo%d” % i setattr(cls,innerdynamo.__name__,innerdynamo) for i in range(2): add_dynamo(Dynamo, i) d=Dynamo() d.dynamo0() d.dynamo1() Which should print: in dynamo 0 in dynamo 1
I do not understand how execlp() works in Linux
this prototype: int execlp(const char *file, const char *arg, …); Says that execlp ìs a variable argument function. It takes 2 const char *. The rest of the arguments, if any, are the additional arguments to hand over to program we want to run – also char * – all these are C strings (and … Read more
Redirecting exec output to a buffer or file
For sending the output to another file (I’m leaving out error checking to focus on the important details): if (fork() == 0) { // child int fd = open(file, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR); dup2(fd, 1); // make stdout go to file dup2(fd, 2); // make stderr go to file – you may choose … Read more
Executing a Java application in a separate process
This is a synthesis of some of the other answers that have been provided. The Java system properties provide enough information to come up with the path to the java command and the classpath in what, I think, is a platform independent way. public final class JavaProcess { private JavaProcess() {} public static int exec(Class … Read more
Why doesn’t exec work in a function with a subfunction?
Correct. You can’t use exec in a function that has a subfunction, unless you specify a context. From the docs: If exec is used in a function and the function contains a nested block with free variables, the compiler will raise a SyntaxError unless the exec explicitly specifies the local namespace for the exec. (In … Read more
sh command: exec 2>&1
Technically speaking it duplicates, or copies, stderr onto stdout. Usually you don’t need the exec to perform this. A more typical use of exec with file descriptors is to indicate that you want to assign a file to an unused file descriptor, e.g. exec 35< my_input BTW Don’t forget that the sequence of declaration when … Read more
How do I launch a completely independent process from a Java program?
There is a parent child relation between your processes and you have to break that. For Windows you can try: Runtime.getRuntime().exec(“cmd /c start editor.exe”); For Linux the process seem to run detached anyway, no nohup necessary. I tried it with gvim, midori and acroread. import java.io.IOException; public class Exec { public static void main(String[] args) … Read more
What are the differences of system(), exec() and shell_exec() in PHP?
exec — Execute an external program system — Execute an external program and display the output shell_exec — Execute command via shell and return the complete output as a string so if you don’t need the output, I would go with exec. Further details: http://php.net/manual/en/function.exec.php http://php.net/manual/en/function.system.php http://php.net/shell_exec