utmp(5) File Formats Manual utmp(5)
Name
utmp, wtmp - login records
Syntax
#include <utmp.h>
Description
The file records information about who is currently using the system. The file is a sequence of entries with the following structure
declared in the include file:
struct utmp {
char ut_line[8]; /* tty name */
char ut_name[8]; /* user id */
char ut_host[16]; /* host name, if remote */
long ut_time; /* time on */
};
This structure gives the name of the special file associated with the user's terminal, the user's login name, and the time of the login in
the form of
The file records all logins and logouts. A null user name indicates a logout on the associated terminal. A terminal referenced with a
tilde (~) indicates that the system was rebooted at the indicated time. The adjacent pair of entries with terminal names referenced by a
vertical bar (|) or a right brace (}) indicate the system-maintained time just before and just after a command has changed the system's
timeframe.
The file is maintained by and Neither of these programs creates the file, so, if it is removed, record-keeping is turned off. It is summa-
rized by
Files
See Also
last(1), lastcomm(1), login(1), who(1), ac(8), init(8)
utmp(5)