SUMMARY: nohup of process

From: Jacques Rall (
Date: Sun Feb 02 1997 - 22:27:15 CST

Original question:

Dear SMs,

How can I nohup a process that is already running?


        # ./remotebackup
        ^Z[1] + Stopped (SIGTSTP) ./remotebackup
        # bg
        [1] ./remotebackup&
Now I want to nohup the process which would allow me to log off.
Something like 'nohup -p <pid>' would be great.



It can't be done. Once a process has been kicked of without the nohup
there is no way to nohup it while it is running.

"You can't. Once a process is started, its response to signals
like 'hangup' cannot be changed externally.

The way 'nohup' works is by using 'sigvec' or 'signal' to ignore
and 'quit' signals. Then when it spawns the desired child process,
child inherits its signal response behavior from its parent, so if
parent ignores 'hangup' or 'quit', then the child will too.

Once the child has started, its signal-handling is set, and no
process can change it. Only the child process itself can change its
  - Michael J. Maciolek

Nohupped process utility:

We do have an
inhouse process called psh which allows one to put a process in
exit the login then at a later time attach the running process so
that output is directed to the new login screen (Solaris 2.x).
The binary has to be compiled with a local library, however so system
utilities are out."
  - W. Frank Lowe

Thanks to *

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