NSTask: program launching another program, how to do?

Question

I want to do with an NSTask what I am able to do in the terminal via

$ myprogram myfile.ext

I know that myprogram (I don't have any control on this program) launches another program myauxprogram. Furthermore, the path to myprogram is path1 and the path to myprogram is path2.

If I do

 NSTask * myTask = [[NSTask alloc] init];

 NSArray * arguments = @[@"myfile.ext"] ;

 [myTask setCurrentDirectoryPath:[URLOfTheFolder path]];
 [myTask setLaunchPath:@"/path1/myprogram"];
 [myTask setArguments:arguments];

 [myTask launch] ;

I get the following error sh: myauxprogam: command not found

If I create a symbol link in path1 to myauxprogram, the problem is the same.

Answer 1

The problem was:

You need to [myTask setEnvironment:...] so that the task knows which are the environment variables (PATH, etc.)

Answer 2

It looks like you mostly have the idea, you're just missing a few key elements. NSTask should have a defined LaunchPath, such as /usr/bin/sh, /usr/bin, etc. from there depending on the type of path you're requiring you set up your arguments and options.

NSTask *auxTask;
NSTask *auxPath = @"./path1/myprogram";        // period might be needed
NSTask *auxArgs = @"myfile.ext";

auxTask = [[NSTask alloc] init];
[auxTask setLaunchPath:@"/usr/bin/sh"];         // use shell

[auxTask setArguments:[NSArray arrayWithObjects:
                             @"-c",             // -c will exec as shell cmd
                             auxPath,
                             auxArgs,
                             nil]];

    // using `try` is optional

    @try
    {
        [auxTask launch];
    }
    @catch(id exc)
    {
        auxTaskSuccess = NO;
    }
    [auxTask release];

return;

No idea if this works, but this is the way you would likely set things up. If you run into issues with errors or the NSTask failing you can set up an NSLog with the auxTask NSArray to see exactly what it's doing.