GIML: How to execute other programs

I have have never seen this work on a non-unix system.

The execute command

This command takes the name of the command (give it the full path) and a list of parameters. The function returns streams for input and output. 
val execute = fn : string * string list -> instream * outstream
To find out the full path name of a command such as ls try which ls at the unix prompt - on my system this gives /usr/bin/ls

Example: who

This executes the unix who command - we see the first two users: 
val (a,_) = execute("/usr/bin/who",[]);
input_line a;
input_line a;
close_in a;

Example: A Sharespearean insult from America

(* A function to return all the data from a stream into a line list *) fun streamToList f_in = if end_of_stream f_in then (close_in f_in;nil) else input_line f_in :: streamToList f_in; (* See lesson seven for details of filter *) fun filter f nil = nil | filter f (h::t) = if f h then h::filter f t else filter f t; (* prefix returns true iff "small" is a prefix of "big" *) fun prefix small big = (size big > size small) andalso substring(big,0,size small)=small; (* execute the telnet command to connect to the Web server at nova *) val (x,y) = execute("/usr/bin/telnet", ["nsu.acast.nova.edu","80"]); (* send the GET command to the Web server - i.e. pretend to be a browser *) output(y,"GET /Inter-Links/cgi-bin/bard.pl HTTP/1.0\n\n"); (* flush the output as it sits in the buffer otherwise *) flush_out y; (* a page of html comes back - to stream x the line we want is prefixed by <li> *) val insult = filter (prefix "<li>")(streamToList x); (* The connection get broken anyway - this closes the process *) close_out y;