nohup
—
invoke a command immune to hangups
The nohup
command allows the specified utility to be
protected from termination if the user should become logged out (for example,
due to a modem line or TCP/IP connection being dropped). To do this,
nohup
sets the SIGHUP
signal(3) (“terminal line
hangup”) to be ignored, then executes utility
along with any arguments.
If the standard output is a terminal, the standard output is
appended to the file nohup.out in the current
directory. If standard error is a terminal, it is directed to the same place
as the standard output. If the output file nohup.out
cannot be created in the current directory, nohup
attempts to create the file in the user's home directory. If the file
nohup.out cannot be created, either in the current
directory or the user's home directory, nohup
will
exit without invoking utility, with an exit value as
described below.
The following variable is used by nohup
:
HOME
- User's home directory.
The nohup
utility exits with one of the following
values:
- 126
- The utility was found but could not be invoked.
- 127
- The utility could not be found or an error occurred
in
nohup
.
Otherwise, the exit status of nohup
will
be that of utility.
The nohup
command is expected to be
IEEE Std 1003.2 (“POSIX.2”) compatible.