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.
exec without arguments shows name and arguments of the currently
running subprocess in this window. Only one subprocess can be running per
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.