link popen
September 28, 1992; Ronald Florence
This file is in the public domain.
Contents:
popen(command, mode)
mode == "w" writes to a pipe
mode == "r" reads from a pipe
pclose(pipe)
On systems without real pipes (ms-dos), popen and pclose imitate
pipes; pclose must be called after popen. The code should run
faster on ms-dos if dir in tempfile() points to a directory on a
virtual disk.
On systems with real pipes, popen & pclose open and close a pipe.