SunOS man pages : nohup (1)
User Commands nohup(1)
NAME
nohup - run a command immune to hangups
SYNOPSIS
/usr/bin/nohup command [ argument ... ]
/usr/xpg4/bin/nohup command [ argument ... ]
DESCRIPTION
The nohup utility invokes the named command with the argu-
ments supplied. When the command is invoked, nohup arranges
for the SIGHUP signal to be ignored by the process.
The nohup utility can be used when it is known that command
will take a long time to run and the user wants to logout of
the terminal; when a shell exits, the system sends its chil-
dren SIGHUP signals, which by default cause them to be
killed. All stopped, running, and background jobs will
ignore SIGHUP and continue running, if their invocation is
preceded by the nohup command or if the process programmati-
cally has chosen to ignore SIGHUP.
/usr/bin/nohup
Processes run by /usr/bin/nohup are immune to SIGHUP
(hangup) and SIGQUIT (quit) signals.
/usr/xpg4/bin/nohup
Processes run by /usr/xpg4/bin/nohup are immune to SIGHUP.
The nohup utility does not arrange to make processes immune
to a SIGTERM (terminate) signal, so unless they arrange to
be immune to SIGTERM or the shell makes them immune to
SIGTERM, they will receive it.
If nohup.out is not writable in the current directory, out-
put is redirected to $HOME/nohup.out. If a file is created,
the file will have read and write permission (600, see
chmod(1)). If the standard error is a terminal, it is
redirected to the standard output, otherwise it is not
redirected. The priority of the process run by nohup is not
altered.
OPERANDS
The following operands are supported:
command
The name of a command that is to be invoked. If the
command operand names any of the special
shell_builtins(1) utilities, the results are unde-
fined.
argument
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User Commands nohup(1)
Any string to be supplied as an argument when invoking
the command operand.
EXAMPLES
Example 1: Applying nohup to pipelines or command lists
It is frequently desirable to apply nohup to pipelines or
lists of commands. This can be done only by placing pipe-
lines and command lists in a single file, called a shell
script. One can then issue:
example$ nohup sh file
and the nohup applies to everything in file. If the shell
script file is to be executed often, then the need to type
sh can be eliminated by giving file execute permission.
Add an ampersand and the contents of file are run in the
background with interrupts also ignored (see sh(1)):
example$ nohup file &
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of nohup: LC_CTYPE,
LC_MESSAGES, PATH, and NLSPATH.
HOME Determine the path name of the user's home directory:
if the output file nohup.out cannot be created in the
current directory, the nohup command will use the
directory named by HOME to create the file.
EXIT STATUS
The following exit values are returned:
126 command was found but could not be invoked.
127 An error occurred in nohup, or command could not be
found
Otherwise, the exit values of nohup will be that of the com-
mand operand.
FILES
nohup.out
the output file of the nohup execution if standard
output is a terminal and if the current directory is
writable.
$HOME/nohup.out
the output file of the nohup execution if standard
output is a terminal and if the current directory is
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User Commands nohup(1)
not writable.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
/usr/bin/nohup
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
| CSI | enabled |
|_____________________________|_____________________________|
/usr/xpg4/bin/nohup
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWxcu4 |
|_____________________________|_____________________________|
| CSI | enabled |
|_____________________________|_____________________________|
SEE ALSO
batch(1), chmod(1), csh(1), ksh(1), nice(1), sh(1),
shell_builtins(1), signal(3C), attributes(5), environ(5),
XPG4(5)
WARNINGS
If you are running the Korn shell ( ksh(1)) as your login
shell, and have nohup'ed jobs running when you attempt to
logout, you will be warned with the message
You have jobs running.
You will then need to logout a second time to actually
logout; however, your background jobs will continue to run.
NOTES
The C-shell ( csh(1)) has a built-in command nohup that pro-
vides immunity from SIGHUP, but does not redirect output to
nohup.out. Commands executed with `&' are automatically
immune to HUP signals while in the background.
nohup does not recognize command sequences. In the case of
the following command,
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User Commands nohup(1)
example$ nohup command1; command2
the nohup utility applies only to command1. The command,
example$ nohup (command1; command2)
is syntactically incorrect.
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