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.TH reptyr 1 "03 Feb 2011"
reptyr \- Reparent a running program to a new terminal
.B reptyr
.B reptyr \-l
.B reptyr
is a utility for taking an existing running program and
attaching it to a new terminal. Started a long-running process over
ssh, but have to leave and don't want to interrupt it? Just start a
screen, use
.B reptyr
to grab it, and then kill the ssh session and head
on home.
.B reptyr
works by attaching to the target program using
.BR ptrace (2),
redirecting relevant file descriptors, and changing the program's controlling
terminal (See
.BR tty (4))
It is this last detail that makes
.B reptyr
work much better than alternatives such as
.BR retty (1).
After attaching a program, the program will appear to be either backgrounded or
suspended to the shell it was launched from (depending on the shell). For
maximal safety you can run
bg; disown
in the old shell to remove the association with the program, but
.B reptyr
will attempt to ensure that the target program remains running even if you close
the shell without doing so.
.B \-l
Instead of attaching to a new process, create a new pty pair, proxy the master
end to the current terminal, and then print the name of the slave pty. This can
be passed to e.g.
.B gdb\'s
.I set inferior-tty
.B \-s
By default, reptyr will move any file descriptors in the target that were
connected to the target's controlling terminal to point to the new terminal. The
.B -s
option will cause reptyr to unconditionally attach file descriptors 0, 1, and 2
in the target, even if the target has no controlling terminal or they are not
connected to a terminal.
.B \-v
Print the version of
.B reptyr
and exit.
.B \-h
Print a usage message and exit.
.B reptyr
depends on the
.BR ptrace (2)
system call to attach to the remote program. On Ubuntu Maverick and higher, this
ability is disabled by default for security reasons. You can enable it
temporarily by doing
# echo 0 > /proc/sys/kernel/yama/ptrace_scope
as root, or permanently by editing the file
.IR /etc/sysctl.d/10-ptrace.conf ,
which also contains more information about this setting.
When attaching to some curses programs, they will not redraw the screen right
away, and a
.B ^L
or similar will be needed to force a redraw.
Similarly, after attaching to certain programs, the old terminal will be left in
an odd state, and a
.B clear
or even
.B reset
may be required before the old terminal is usable again.
Attaching to rtorrent (and probably some other apps) doesn't work right
(rtorrent stops accepting input) (The problem is that rtorrent is using epoll to
poll stdin, and we don't update the internal reference that the epoll fd has to
the old tty).
Attaching to a process with children doesn't work right. This should be possible
to fix -- I just need to ptrace each child individually and do the same games to
Attaching a
.BR less (1)
process doesn't work if you have a
.I .lessfilter
file, as
.BR less
leaves around a zombie child in this case. This could be worked around.
Bugs should be reported to the author (see below) or via the issue tracker on
reptyr was written by Nelson Elhage <>.
.BR neercs (1),
.BR screen (1)