1nohup(1) User Commands nohup(1)
2
6 nohup - run a command immune to hangups
7
9 /usr/bin/nohup command [argument]...
10 /usr/bin/nohup -p [-Fa] pid [pid]...
13 /usr/bin/nohup -g [-Fa] gpid [gpid]...
16 /usr/xpg4/bin/nohup command [argument]...
19
22 The nohup utility invokes the named command with the arguments sup‐
23 plied. When the command is invoked, nohup arranges for the SIGHUP sig‐
24 nal to be ignored by the process.
25 When invoked with the -p or -g flags, nohup arranges for processes
28 already running as identified by a list of process IDs or a list of
29 process group IDs to become immune to hangups.
30 The nohup utility can be used when it is known that command takes a
33 long time to run and the user wants to log out of the terminal. When a
34 shell exits, the system sends its children SIGHUP signals, which by
35 default cause them to be killed. All stopped, running, and background
36 jobs ignores SIGHUP and continue running, if their invocation is pre‐
37 ceded by the nohup command or if the process programmatically has cho‐
38 sen to ignore SIGHUP.
39 /usr/bin/nohup Processes run by /usr/bin/nohup are immune
41 to SIGHUP (hangup) and SIGQUIT (quit) sig‐
42 nals.
43 /usr/bin/nohup -p [-Fa] Processes specified by ID are made immune to
46 SIGHUP and SIGQUIT, and all output to the
47 controlling terminal is redirected to
48 nohup.out. If -F is specified, nohup forces
49 control of each process. If -a is specified,
50 nohup changes the signal disposition of
51 SIGHUP and SIGQUIT even if the process has
52 installed a handler for either signal.
53 /usr/bin/nohup -g [-Fa] Every process in the same process group as
56 the processes specified by ID are made
57 immune to SIGHUP and SIGQUIT, and all output
58 to the controlling terminal is redirected to
59 nohup.out. If -F is specified, nohup forces
60 control of each process. If -a is specified,
61 nohup changes the signal disposition of
62 SIGHUP and SIGQUIT even if the process has
63 installed a handler for either signal.
64 /usr/xpg4/bin/nohup Processes run by /usr/xpg4/bin/nohup are
67 immune to SIGHUP.
68 The nohup utility does not arrange to make
70 processes immune to a SIGTERM (terminate)
71 signal, so unless they arrange to be immune
72 to SIGTERM or the shell makes them immune to
73 SIGTERM, they will receive it.
74 If nohup.out is not writable in the current
76 directory, output is redirected to
77 $HOME/nohup.out. If a file is created, the
78 file has read and write permission (600. See
79 chmod(1). If the standard error is a termi‐
80 nal, it is redirected to the standard out‐
81 put, otherwise it is not redirected. The
82 priority of the process run by nohup is not
83 altered.
84
87 The following options are supported:
88 -a Always changes the signal disposition of target processes. This
90 option is valid only when specified with -p or -g.
91 -F Force. Grabs the target processes even if another process has
94 control. This option is valid only when specified with -p or -g.
95 -g Operates on a list of process groups. This option is not valid
98 with -p.
99 -p Operates on a list of processes. This option is not valid with
102 -g.
103
106 The following operands are supported:
107 pid A decimal process ID to be manipulated by nohup -p.
109 pgid A decimal process group ID to be manipulated by nohup -g.
112 command The name of a command that is to be invoked. If the command
115 operand names any of the special shell_builtins(1) utili‐
116 ties, the results are undefined.
117 argument Any string to be supplied as an argument when invoking the
120 command operand.
121
124 Caution should be exercised when using the -F flag. Imposing two con‐
125 trolling processes on one victim process can lead to chaos. Safety is
126 assured only if the primary controlling process, typically a debugger,
127 has stopped the victim process and the primary controlling process is
128 doing nothing at the moment of application of the proc tool in ques‐
129 tion.
130
132 Example 1 Applying nohup to pipelines or command lists
133 It is frequently desirable to apply nohup to pipelines or lists of com‐
136 mands. This can be done only by placing pipelines and command lists in
137 a single file, called a shell script. One can then issue:
138 example$ nohup sh file
141 and the nohup applies to everything in file. If the shell script file
146 is to be executed often, then the need to type sh can be eliminated by
147 giving file execute permission.
148 Add an ampersand and the contents of file are run in the background
152 with interrupts also ignored (see sh(1)):
153 example$ nohup file &
156 Example 2 Applying nohup -p to a process
160 example$ long_running_command &
162 example$ nohup -p `pgrep long_running_command`
163 Example 3 Applying nohup -g to a process group
167 example$ make &
169 example$ ps -o sid -p $$
170 SID
171 81079
172 example$ nohup -g `pgrep -s 81079 make`
173
177 See environ(5) for descriptions of the following environment variables
178 that affect the execution of nohup: LANG, LC_ALL, LC_CTYPE, LC_MES‐
179 SAGES, PATH, NLSPATH, and PATH.
180 HOME Determine the path name of the user's home directory: if the
182 output file nohup.out cannot be created in the current direc‐
183 tory, the nohup command uses the directory named by HOME to
184 create the file.
185
188 The following exit values are returned:
189 126 command was found but could not be invoked.
191 127 An error occurred in nohup, or command could not be found
194 Otherwise, the exit values of nohup are those of the command operand.
198
200 nohup.out The output file of the nohup execution if standard
201 output is a terminal and if the current directory is
202 writable.
203 $HOME/nohup.out The output file of the nohup execution if standard
206 output is a terminal and if the current directory is
207 not writable.
208
211 See attributes(5) for descriptions of the following attributes:
212 /usr/bin/nohup
214 ┌─────────────────────────────┬─────────────────────────────┐
215 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
216 ├─────────────────────────────┼─────────────────────────────┤
217 │Availability │SUNWcsu │
218 ├─────────────────────────────┼─────────────────────────────┤
219 │CSI │Enabled │
220 └─────────────────────────────┴─────────────────────────────┘
221 /usr/xpg4/bin/nohup
223 ┌─────────────────────────────┬─────────────────────────────┐
224 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
225 ├─────────────────────────────┼─────────────────────────────┤
226 │Availability │SUNWxcu4 │
227 ├─────────────────────────────┼─────────────────────────────┤
228 │CSI │Enabled │
229 ├─────────────────────────────┼─────────────────────────────┤
230 │Interface Stability │Standard │
231 └─────────────────────────────┴─────────────────────────────┘
232
234 batch(1), chmod(1), csh(1), ksh(1), nice(1), pgrep(1), proc(1), ps(1),
235 sh(1), shell_builtins(1), signal(3C), proc(4), attributes(5), envi‐
236 ron(5), standards(5)
237
239 If you are running the Korn shell (ksh(1)) as your login shell, and
240 have nohup'ed jobs running when you attempt to log out, you are warned
241 with the message:
242 You have jobs running.
244 You need to log out a second time to actually log out. However, your
249 background jobs continues to run.
250
252 The C-shell (csh(1)) has a built-in command nohup that provides immu‐
253 nity from SIGHUP, but does not redirect output to nohup.out. Commands
254 executed with `&' are automatically immune to HUP signals while in the
255 background.
256 nohup does not recognize command sequences. In the case of the follow‐
259 ing command,
260 example$ nohup command1; command2
262 the nohup utility applies only to command1. The command,
267 example$ nohup (command1; command2)
269 is syntactically incorrect.
274SunOS 5.11 19 Jun 2006 nohup(1)