Unix as a Second Language

Concatenating strings and using += in bash

There are many ways to concatenate strings when you're using bash and += might just surprise you!

Extracting substrings on Linux

Linux provides a nice selection of commands for pulling substrings from text, but each has its own way of working.

Running a Linux terminal in your Windows browser

Here's an introduction to running a Linux terminal inside a browser and some of the tools available to you.

Using strace and ltrace to help with troubleshooting on Linux

strace and ltrace provide a flood of information about system and library calls being made by Linux processes, and sorting through it all can help discover the cause of problems.

How to cheat on Wordle using Linux

Figuring out Wordle can be a lot of fun, but if it gets too frustrating, this Linux bash script can be your friend. Enjoy taking a look at how the cheating process works.

Using whereis, whatis, and which to find out about commands on Linux

The whereis, whatis and which commands can provide information on Linux commands, but in spite of names that appear related, they provide very different answers.

Creating a quick calculation function on Linux

Need to perform a long series of calculations? Let's look at a cool trick for making it easier.

2 ways to remove duplicate lines from Linux files

Linux awk and uniq commands offer options for cutting out duplicate lines from Linux files.

Using the btrfsck file-checing command on Linux

The btrsfck command allows you to check the integrity of a btrfs file system. As file systems migrate to this newer file system format, this command is increasingly important.

Using the ldd command on Linux

The ldd displays the shared object files that a particular Linux command needs to run.

Using fail2ban on Fedora

Fail2ban can detect attempts to connect to authenticated services such as ssh and put the offending connections in "jail". This article provides information on how to install, configure and test the tool on Fedora.

Learning to script on Linux using bash

Here are some basic skills to get started with bash, one of the best shells for preparing and using scripts on Linux.

Using ClamAV to detect viruses on Linux

The ClamAV command can identify and relocate files on Linux that have been infected by viruses, but not remove the viruses themselves.

Using pipes on Linux to get a lot more done

Piping commands together on the Linux command line lets you get a lot more done with little effort. This post demonstrates this with a couple very useful commands.

Using the Linux host command to dig out DNS details

The Linux host command can retrieve a lot of useful information from the domain name service, but has a lot of options that you need to understand to get started.

Using the Linux fold command to make text more readable

In Linux, the fold command can wrap text that displays wider than a monitor's width.

Using the seq command to generate numeric sequences

The Linux seq command generates lists of numbers, but it has many subtleties to master.

Turn tabs into spaces on Linux and vice versa

The Linux expand and unexpand commands can turn tabs into spaces and spaces into tabs, and the sed and awk commands can help.

Hashing out the hash command on Linux

The Linux hash command provides information about commands on your system or those you've run recently, but what you see depends on the shell you are using.

Using the Linux look command to select lines from files

The look command allows you to extract lines from files that begin with a certain string. It's easy to use when you want to find words stored in the system's words file but can be little finicky when you want to use it on other text...