Login--last*

Small Q: Why hurt so far can also be done, and comfort, but must be in the side. ----Most novel

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The last command is used to display the user's most recent logon information. The last command is executed separately, and the/var/log/wtmp file is read by default, and all the user lists of the logged-in system for the contents of the file are displayed;
Btmp can be displayed in more detail, can display remote login
The utmp file holds information about the users currently in the system
Format:
Last [-R] [-num] [-N num] [-adiowx] [-f file] [-t YYYYMMDDHHMMSS] [name ...] [TTY ...]
Options:
-A will log on to the system's host name or IP address, displayed on the last line
-D convert IP address to host name
-f Specifies the record file, the default is to display the records of the Wtmp file under the/var/log directory, but btmp can be displayed in the/var/log directory

Richer and can display remote logins, such as SSH logins, including failed login requests.
-i-i Displays the status of specific IP logins, which are tracked.
-N < Show columns > or-< Show columns > set the number of displayed columns for a list
-R does not display the host name or IP of the login system
-t display information before YYYYMMDDHHMMSS
-X shows the history of system shutdown, user login, and exit

First column: User name
Second column: End position. pts/0 (pseudo terminal) means a remote connection from a user such as SSH or Telnet. TTY (teletypewriter) means a user connected directly to a computer or locally connected
Third column: Login IP or kernel. If you see: 0.0 or nothing, this means that the user is connected via a local terminal. In addition to restarting the activity, the kernel version is displayed in the status.
Fourth column: Start time
Fifth column: End time (still login in has not exited down until normal shutdown crash until shutdown is forced)
Sixth column: Duration
Example:
Show N Records
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the IP put it to the last display
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Specify the/var/log/btmp file to view information about users logged on to the system
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Show information prior to YYYYMMDDHHMMSS (20150110093000)
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The lastb command is used to display a login list of user errors, which can discover the system's logon exceptions. Executes the LASTB command separately, it reads the file in the/var/log directory named Btmp, and displays the list of users who have logged on to the file with a log-in failure.

Format: Lastb [-adrx][-f < record file >][-n < show number of columns >][account name ...] [Terminal number ...]
Options:
-A: Displays the host name or IP address from where the system was logged on to the last line;

-D: Convert IP address to host name;
-F: < record file;: Specify the record file;
-N: < shows the number of columns > or-< display columns;: Sets the number of displayed columns for the list;
-R: Does not display the host name or IP address of the login system;
-X: Displays information such as system shutdown, reboot, and execution level changes.

The first run of the LASTB command will report an error:

LASTB:/var/log/btmp:no Such file or directory perhaps this file is removed by the operator to prevent logging Lastb inf O.

Just create this nonexistent file.
Example:

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The lastlog command is used to display the most recent logon information for all users in the system. The Lastlog file is queried each time a user logs on. You can use the Lastlog command to check the last logon time for a particular user and format the output of the last logon log/var/log/lastlog. It displays the login name, port number (TTY), and last logon time based on the UID sort. If a user has never logged in, Lastlog displays **never logged**. Note You need to run the command as root.

Format: Lastlog option

Options:

-b< days;: Displays the login information before the specified number of days;

-H: Displays the help information for the call-up order;

-t< days;: Displays login information since the specified number of days;

-u< user name;: Displays the most recent login information for the specified user.
Example:

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Login--last*