Differences between version 7 and predecessor to the previous major change of SIGHUP.
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| Newer page: | version 7 | Last edited on Monday, March 10, 2003 11:42:54 pm | by NicBellamy | Revert |
| Older page: | version 4 | Last edited on Monday, November 11, 2002 11:05:48 pm | by CraigBox | Revert |
@@ -1,9 +1,15 @@
!!!Signal: Hangup
-This signal is generated by the kernel when your controlling terminal goes away. Or, in simplier terms, when you close the Xterm, or hang up a modem. Since daemons run in the background and don't have a controlling terminal, they often use SIGHUP to signal that they should reread their configuration files. This can cause issues with some programs that work as both a daemon and an interactive program, such as fetchmail(1).
-An example of a daemon that rereads it's configuration file on SIGHUP is init(1
), the first process created (which is responsible for creating all other processes, like getty for logging in). If you edit /etc/inittab, its configuration file, you can do
+This signal is generated by the kernel when your controlling terminal goes away to the terminals ProcessGroup
. Or, in simplier terms, when you close the Xterm, or hang up a modem. Since daemons run in the background and don't have a controlling terminal, they often use SIGHUP to signal that they should reread their configuration files. This can cause issues with some programs that work as both a daemon and an interactive program, such as fetchmail(1).
+An example of a daemon that rereads it's configuration file on SIGHUP is init(8
), the first process created (which is responsible for creating all other processes, like getty for logging in). If you edit /etc/inittab, its configuration file, you can do
kill -HUP 1
-and it will re-read the config file.
+and it will re-read the config file (note that the correct way to do this is to use [telinit])
.
To restart an inetd(8) service, you send a hangup to inetd:
killall -HUP inetd
+
+You can prevent a process from recieving a SIGHUP signal by using the command nohup(1)
+
+For example:
+ nohup wget http://www.example.com/ &
+will run "wget" that is not attached to a terminal (and therefore doesn't recieve a SIGHUP) when you disconnect. This is useful if the file you are downloading is long, but you want to logout before the download is complete. The "&" at the end is used to put the command into the background.
