Question

Here is my code:

task = [[NSTask alloc] init];
[task setCurrentDirectoryPath:@"/applications/jarvis/brain/"];
[task setLaunchPath:@"/applications/jarvis/brain/server.sh"];

NSPipe * out = [NSPipe pipe];
[task setStandardOutput:out];

[task launch];
[task waitUntilExit];
[task release];

NSFileHandle * read = [out fileHandleForReading];
NSData * dataRead = [read readDataToEndOfFile];
NSString * stringRead = [[[NSString alloc] initWithData:dataRead encoding:NSUTF8StringEncoding] autorelease];

So I’m trying to replicate this:

cd /applications/jarvis/brain/
./server.sh

but using NSTask in objective-c.

For some reason though, when I run this code, stringRead, returns nothing. It should return what terminal is returning when I launch the .sh file. Correct?

Any ideas?

Elijah

Answer 1

Xcode Bug
There’s a bug in Xcode that stops it from printing any output after a a new task using standard output is launched (it collects all output, but no longer prints anything). You’re going to have to call [task setStandardInput:[NSPipe pipe]] to get it to show output again (or, alternatively, have the task print to stderr instead of stdout).

---

Suggestion for final code:

NSTask *server = [NSTask new];
[server setLaunchPath:@"/bin/sh"];
[server setArguments:[NSArray arrayWithObject:@"/path/to/server.sh"]];
[server setCurrentDirectoryPath:@"/path/to/current/directory/"];

NSPipe *outputPipe = [NSPipe pipe];
[server setStandardInput:[NSPipe pipe]];
[server setStandardOutput:outputPipe];

[server launch];
[server waitUntilExit]; // Alternatively, make it asynchronous.
[server release];

NSData *outputData = [[outputPipe fileHandleForReading] readDataToEndOfFile];
NSString *outputString = [[[NSString alloc] initWithData:outputData encoding:NSUTF8StringEncoding] autorelease]; // Autorelease optional, depending on usage.