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What is the lastlog command?
lastlog is a program available on most Linux distributions. It formats and prints the contents of the last login log file, /var/log/lastlog (which is a usually a very sparse file), including the login name, port, and last login date and time.
What do lastlog and Lastb commands do?
On the Linux systems there are three standard commands that show the information about last logged in users: last , lastb , and lastlog . The output of these commands include: login-name, last login time, IP address, port etc. And sometimes, to keep anonymity, it is required to erase last login history.
What file does the last command retrieve information from?
log file
The last command displays information about the last logged-in users. It’s pretty convenient and handy when we need to track login activities or investigate a possible security breach. The last command will, by default, take the system log file /var/log/wtmp as the data source to generate reports.
Why is lastlog so large?
Answer. The file is a sparse file and is not actually taking up as much physical space as it shows. lastlog records the last login of each user. The large size merely shows you the potential size of the file if there were a maximum amount of users (around 2^32 users).
What are the options for the lastlog command?
The options which apply to the lastlog command are: Print only lastlog records older than DAYS . Display help message and exit. Print the lastlog records more recent than DAYS . Print the lastlog record for user with specified LOGIN only. The -t flag overrides the use of -u .
How can I check my last login on lastlog?
To generate a list of all the accounts that have never been logged into, use a command like this: The records in the lastlog command output are listed in UID order – from root to the user with the highest UID in your /etc/passwd file. This is due to the format of the lastlog (/var/log/lastlog) file itself.
How big is the lastlog file in passwd?
The lastlog file is a database which contains info on the last login of each user. You should not rotate it. It is a sparse file, so its size on the disk is usually much smaller than the one shown by “ls -l” (which can indicate a really big file if you have in passwd users with a high UID).
How can I check the size of my lastlog file?
You can use a command like this to see whether your lastlog file is sparse. Notice that the size on the left (1.3M) is smaller than the reported size of 1642500 bytes. Notice that the size shown on the left (1.3M) is smaller than the one the ls –l normally displays (1.6M).