There are many log files in linux systems, but we will outline six that are most important.

1. /var/log/cups/ - This directory stores the log files for the printing system CUPS.
2. /var/log/news/ - This Directory stores messages for the news system.
3. /var/log/boot.msg - When the system boots, all boot script messages are displayed on the first virtual console. This opften happens so fast that you cannot read all the messages. You can, however, read the boot messages including the output from start scripts of services in this file. You can display messages from the kernel during the boot procedure later with the command dmesg (/bin/dmesg).
4. /var/log/mail - Messages from the mail system are written to this file. because this system often generates a lot of messages, there are additional log files: /var/log/mail.err
   /var/log/mail.info
   /var/log/mail.warn
5. /var/log/wtmp - This file contain information about which user was logger in from where and for how long (since the file was created). This file contents are in binary form and can only be displayed with the command last (/usr/bin/last). Because of the binary format, it is difficult to manipulate entries in this file.
6. /var/log/lastlog - This file contains information about user’s last login, from where, and for how long. You can view the contents of this command with the command lastlog.

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