User commands and logs
The log with the name
auth.log records authorizations – that is, logons and logoffs on a system since the last time the system was booted (Figure 4). This information can be invaluable in checking patterns of usage and detecting any departures from the norm. Only the root user can view it.
user.log records the logins and logouts for the entire system, as well as any warnings that might indicate potential problems (Figure 5). In other words, this log is often a convenient point for troubleshooting general problems. As you might expect, only root can read this log.
Most commands have two types of options: Unix-like ones that are preceded by a single hyphen and are typically a single letter, and GNU options that are preceded by two hyphens and are usually a complete phrase that describes what they do. You can tell how old many of the user-related commands are by the fact that several of them have no GNU options whatsoever. In other words, when you are administering users, you are really getting down to the foundations of your operating system.
Buy this article as PDF
But if you are not using the latest Linux kernel, your system is insecure.
Home routers will give room for custom firmware but still comply with FCC rules
Frank Karlitschek will continue to lead the open source ownCloud project
“Xenial Xerus” comes with a new packages format and several improvements for the enterprise.
Linux users can now download and install the Windows code editor
New initiative will address security and interoperability concerns around container technology.
Developers can use RHEL as a development platform without a subscription fee.
Windows users will soon have native access to the Bash shell.
Improvements to SMTP will provide better guarantee of confidentiality
Graphics vendor embraces new reality in Linux graphics