Linux system logging changed with the introduction of systemd. Learn how to use the journalctl command to read and filter system log messages.

The Linux grep command is a string and pattern matching utility that displays matching lines from multiple files. It also works with piped output from other commands. We show you how.

The Linux tail command displays data from the end of a file. It can even display updates that are added to a file in real-time. We show you how to use it.

Add swap space to a Linux computer, or increase the swap space that’s already present, without messing about with partitions. We show you the easy way to tailor your swap space.

The Linux stat command shows you much more detail than ls does. Take a peek behind the curtain with this informative and configurable utility. We’ll show you how to use it.

The Linux which command identifies the executable binary that launches when you issue a command to the shell. If you have different versions of the same program on your computer, you can use which to find out which one the sh...

When you use the Linux du command, you obtain both the actual disk usage and the true size of a file or directory. We’ll explain why these values aren’t the same.

The Linux swappiness value has nothing to do with how much RAM is used before swapping starts. That’s a widely reported and widely believed mistake. We explain what it really is.

The dmesg command lets you peer into the hidden world of the Linux startup processes. Review and monitor hardware device and driver messages from the kernel’s own ring buffer with “the fault finder’s friend...

We use the Linux ls command every day without thinking about it. That’s a pity. Pay it some attention, and you’ll find many useful options—including some you should add to your command-line arsenal....