Call shell script using objective-c - NsTask

Question

I have been working on a command line tool in swift but due to excessive size of the executable(around 10 mb) I need to re-write it in objective-c. Now I am not a fan of objective-c, thanks to it's lengthy syntax. So I have this function which I use to call my shell script and return the output. Can some please convert this into objective-c, I am having a hard time.

func shell(_ args: String) -> String {
    var outstr = ""
    let task = Process()
    task.launchPath = "/bin/sh"
    task.arguments = ["-c", args]
    let pipe = Pipe()
    task.standardOutput = pipe
    task.launch()
    let data = pipe.fileHandleForReading.readDataToEndOfFile()
    if let output = NSString(data: data, encoding: String.Encoding.utf8.rawValue) {
        outstr = output as String
    }
    task.waitUntilExit()
    return outstr
}

then I call this method in swift something like

let shellOutput = shell("sh \(scriptPath) \(arg1) \(arg2)")

before you mark it duplicate or post answers, I really need the shell script output in some variable.

I think you'll find you get better answers by including the ObjC code you have tried to write, and where you are getting stuck. What part are you having a hard time with? — Mattie, Jan 07 '19 at 20:12
I'm going to question the premise here. Why is the 10 MB executable size an issue? What size optimizations have you tried making? What makes you think the Objective C variant would be smaller? — Alexander, Jan 07 '19 at 20:14
@Alexander the size bloat is because of swift not supporting ABI. In objective-c, literally it is of kbs. reason being I think the executable contains all of swift binaries while building — SUMIT NIHALANI, Jan 07 '19 at 20:18
Search SO for "[objective-c] nstask pipe.fileHandleForReading readDataToEndOfFile" and you'll find examples. — Willeke, Jan 07 '19 at 22:37

score 0 · Answer 1 · answered Jan 08 '19 at 05:04

NSString *shell(NSString *args)
{
    NSTask *task = [NSTask new];
    task.launchPath = @"/bin/sh";
    task.arguments = @[ @"-c", args ];
    NSPipe *pipe = [NSPipe new];
    task.standardOutput = pipe;
    [task launch];
    NSData *data = [[pipe fileHandleForReading] readDataToEndOfFile];
    NSString *output = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    [task waitUntilExit];
    return output;
}

Call shell script using objective-c - NsTask

1 Answers1