Cocoa wrapper for an interactive Unix command

cocoa, command-line-tool, interactive-mode, objective-c, unix

Solution

You can use NSTask's `setStandardInput:`, `setStandardOutput:` and `setStandardError:` selectors in conjunction with NSPipe instances to communicate with the launched program.

For example, to read the task's output:

task = [[NSTask alloc] init];
[task setStandardOutput: [NSPipe pipe]];
[task setStandardError: [task standardOutput]]; // Get standard error output too
[task setLaunchPath: @"/usr/bin/gdb"];
[task launch];

You can then obtain an `NSFileHandle` instance that you can use to read the task's output with:

NSFileHandle *readFromMe = [[task standardOutput] fileHandleForReading];

To set up a pipe for sending commands to gdb, you would add

[task setStandardInput: [NSPipe pipe]];

before you launch the task. Then you get the `NSFileHandle` with

NSFileHandle *writeToMe = [[task standardInput] fileHandleForWriting];

Problem

Ok, so I know you can make an NSTask to run command line tools with Objective-C: ``` NSTask *task; task = [[NSTask alloc] init]; [task setLaunchPath: @"/usr/bin/gdb"]; [task launch]; ``` I'm just wondering if there's a way to communicate with interactive command line tools such a as `gdb`. This would involve giving the command inputs based on user interaction (like `run`, `kill` or `quit` with `gdb`) and then reacting based on the information it outputs.

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