shell termination. Different shells also have other methods of controlling and managing SIGHUP, such as the disown facility of ksh. Most modern Linux distributions documentation specify using kill -HUP <processID> to send the SIGHUP signal. Daemon programs sometimes use SIGHUP as a signal to restart themselves, the most common reason for this being to re-read a configuration file that has been changed. Details Symbolic signal names are used because signal numbers can vary across platforms, but XSI-conformant systems allow the use of the numeric constant 1 to be used to indicate a SIGHUP, which the vast majority of systems in fact use. SIGHUP can be handled. That is, programmers can define the action they want to occur upon receiving a SIGHUP, such as calling a function, ignoring it, or restoring the default action. The default action on POSIX-compliant systems is an abnormal termination. References See also Unix signal RS-232 Computer terminal Unix signals