Pipe stdin to, or stdout from, a UNIX shell command. Pipe treats the shell command as if it were a UnixFILE, and returns nil when done. See UnixFILE for details of the access methods. Pipe must be explicitly closed. Do not rely on the garbage collector to do this for you!
A String representing a valid shell command.
A String representing the mode. Valid modes are "w" (pipe to stdin) and "r" (pipe from stdout).
Open the file.
A command line String passed to popen.
A String passed to popen, so should be one of: "r","w"
Closes the pipe, waiting for the command to finish. You must do this explicitly before the Pipe object is garbage collected.
The exit status of the command (an Integer).
A more time-intensive request: