Contents
What is var run utmp?
/var/run/utmp – Contains currently logged in users. /var/log/wtmp – Contains all current and past logins and additional information about system reboots, etc. /var/log/btmp – Contains all bad login attempts.
How do I check my utmp?
We can also use the last command to read the content of the files wtmp, utmp and btmp as well. For example: # last -f /var/log/wtmp ### To open wtmp file and view its content use blow command. # last -f /var/run/utmp ### To see still logged in users view utmp file use last command.
What are wtmp files?
The wtmp file records all logins and logouts. Its format is exactly like utmp except that a null username indicates a logout on the associated terminal.
What is the purpose of utmp, wtmp and btmp files in Linux?
What is the purpose of utmp, wtmp and btmp files in Linux 1 utmp will give you complete picture of users logins at which terminals, logouts, system events and current status of the system, system boot time (used by uptime) etc. 2 wtmp gives historical data of utmp. 3 btmp records only failed login attempts.
What does the file var / run / utmp do?
The file /var/run/utmp allows one to discover information about who is currently using the system. This file will contains information on a user’s logins: on which terminals, logouts, system events and the current status of the system, system boot time (used by uptime) etc.
What does a / var / log / wtmp file do?
/var/log/wtmp file This file is like history for utmp file, i.e. it maintains the logs of all logged in and logged out users (in the past). The last command uses this file to display listing of last logged in users.
Is it necessary to clear utmp in System V?
Clearing ut_id may result in race conditions leading to corrupted utmp entries and potential security holes. Clearing the abovementioned fields by filling them with null bytes is not required by System V semantics, but makes it possible to run many programs which assume BSD semantics and which do not modify utmp.