interact (stdin/out) with command line programs at runtime in C

Question

I think the thing I want to do is called GUI/command line wrapping sftp(1). I need an easy way to start that program and react on its output while running. Additionally I have to be able to send input to it, full interaction is required.

I tried forkpty (emulated TTY), but there wasn't one good example findable using forkpty for that job, instead several warnings about overflows in in arguments and advisories not to use it. Another weird thing about this was the windowsize argument...

Please either give me one or many example(s) on how to call & interact with command line programs in C or another way of integrating sftp in an iPhone GUI

Answer 1

Rejoice! Expect was created to solve exactly your problem. It's based on Tcl, which is not so pleasant, but the tool is pleasant, it's really well designed, and there's a good book by Don Libes, who created the tool.

Expect scripts are written in Tcl, but it is totally easy to integrate a Tcl script into a C program such that other parts of the C program don't even know that Tcl is being used.

Answer 2

Have you used any of the popular scripting languages Ruby/Python/Perl/etc? They all have pretty full featured libraires for opening and communicating with other processes.

the subprocess module in python for example, or Popen in Ruby... there would also be lots of reference material around the web to help you out.

If a GUI was also required you could look at GTK extensions

Answer 3

Instead of calling sftp(1), how about using libssh? It has full sftp subsystem support.