screen: Exec
13.1 Exec
=========
-- Command: exec [[FDPAT] NEWCOMMAND [ARGS ... ]]
(none)
Run a unix subprocess (specified by an executable path NEWCOMMAND
and its optional arguments) in the current window. The flow of
data between newcommands stdin/stdout/stderr, the process
originally started (let us call it "application-process") and
screen itself (window) is controlled by the file descriptor pattern
FDPAT. This pattern is basically a three character sequence
representing stdin, stdout and stderr of newcommand. A dot ('.')
connects the file descriptor to screen. An exclamation mark ('!')
causes the file descriptor to be connected to the
application-process. A colon (':') combines both.
User input will go to newcommand unless newcommand receives the
application-process' output (FDPATs first character is '!' or ':')
or a pipe symbol ('|') is added to the end of FDPAT.
Invoking 'exec' without arguments shows name and arguments of the
currently running subprocess in this window. Only one subprocess
can be running per window.
When a subprocess is running the 'kill' command will affect it
instead of the windows process. Only one subprocess a time can be
running in each window.
Refer to the postscript file 'doc/fdpat.ps' for a confusing
illustration of all 21 possible combinations. Each drawing shows
the digits 2, 1, 0 representing the three file descriptors of
newcommand. The box marked 'W' is usual pty that has the
application-process on its slave side. The box marked 'P' is the
secondary pty that now has screen at its master side.