Learn how to use a host of Linux commands in these 2-minute video tutorials from Sandra Henry-Stocker, author of the Unix as a Second Language blog.
In this Linux tip, we’re going to look at the expand command. It's used to replace tabs in text files with space characters (sometimes referred to as "blanks").
In this Linux tip, we’re going to look at the seq (sequence) command. It provides a very easy way to generate a sequence of numbers and gives you a lot of control.
In this Linux tip, learn how to use the true and false commands. What they do is very simple. The true command generates an exit code of 0 (no problems) and the false command generates a value of 1.
In this Linux tip, learn how to use the fold command. It allows you to limit the length of lines when displaying a text file by "folding" long lines into smaller pieces and, of course, you can save the shortened lines into another file.
In this Linux tip, learn how to use the csplit command. It's a command that lets you split a file into pieces based on its content. For example, you might separate a file based on chapter headings, dates or content separators of some kind. Think of "csplit" as meaning "context split."
In this Linux tip, learn how to use the nethogs command. As the name implies, nethogs will display information on how much processes using or "hogging" your network bandwidth.
In this Linux tip, learn how to use the whois command. It sends requests to what are called WHOIS servers. These servers maintain numerous details on domain registrations. So, when you ask about a particular domain, you get a pile of details.
In this Linux tip, learn how to use the dmesg command. It's a command that displays the content of the kernel message buffer – messages that were sent by various system services such as device drivers. You can view a lot of information that you would normally not see and get insights into how your system is working.
In this Linux tip, learn how to use the free command. It doesn't mean a command that you are not paying for, but one that tells you how much memory – physical and swap – is being used on your Linux system including how much is "free" and how much is available.
In this Linux tip, learn how to use the bpytop command. It's one of many "top" commands (like top and htop) that make it easy to gauge many aspects of system performance on Linux.
In this Linux tip, learn how to use the cheat command. It provides what have come to be called "cheat sheets" on a huge assortment of Linux commands. Once installed, all you have to do is type "cheat" followed by the name of the command for which you want to see sample commands.
In this Linux tip, learn how to use the xargs command. It accepts input that is piped to it and then uses that input as arguments to whatever command you specify.
In this Linux tip, learn how to add comments to your scripts. It's a super easy thing to do and can make it a lot easier for you or someone else to figure out what your script is intended to do – especially if the script is complex or you haven't looked at it in a long time.
In this Linux tip, learn how to use the sar command. The name "sar" stands for "system activity report". It provides details on all aspects of system performance including system load, CPU usage, memory use, paging, swapping, disk usage, device load, network activity and so on.
In this Linux tip, learn how to use the wait command. It's a command that allows you to wait for a process running in the background to finish before you move on to the next command.
In this Linux tip, learn how to use the sleep command. The sleep command introduces a pause on the command line or in a script.
In this Linux tip, learn how to use the export command. It's a bash built-in that allows command line variables to be available to a child process – a second shell or a script that you run.
In this Linux tip, you'll learn two checksum commands -- one that provides an easy way to compare a copy of a file to the original, and one that computes a 256-bit checksum that is cryptographically secure.
In this Linux tip, learn an easy way to do math on the command line using double parentheses. This construct is often used in scripts, but also works just fine on the command line.
In this Linux tip, learn how to use the shuf command -- short for “shuffle”. It randomly rearranges lines from a file or output that is sent to it.
In this Linux tip, learn how to use the nl command. It stands for “number lines” and it does just that.
In this Linux tip, learn how easy it is to install Apache on Fedora. The first thing you need to do is run a command to install the software. Then, you can run other commands to ensure it starts when your system reboots, to view Apache processes, to uninstall it and more.
In this Linux tip, learn how to ask a Linux command for help. You can type the command you want to know about and then add --help. What the command should send back is an explanation of the command's options, maybe a usage example and something about the exit status.
In this Linux tip, learn how to use the bzcat and zcat commands. They allow you to look at the contents of files compressed with the bzip2 and gzip commands without having to uncompress the files first. Instead, these commands uncompress the files and send the output to standard out while the compressed files are left intact.
In this Linux tip, learn how to use bash shell's "debugging mode". It can help you pinpoint problems, especially in long or complicated scripts.
In this Linux tip, learn how to use exiftool. It's an app that you can install on your Linux system to pull metadata from jpg and png files. That metadata provides information such as the date the image was created or last modified, the image size in pixels and the image resolution.
In this Linux tip, learn how to use the help command. It's a command that provides useful information on bash "builtins". Those are commands that are built into, in other words "part of" the bash shell, not executables on their own.
In this Linux tip, learn how to use the traceroute command. It reports on the route taken to reach a remote system and provides timing details for each "hop" along the way (the time between routers).
In this Linux tip, learn how to use the tool called speedtest. It allows you to check the speed of your connection to your Internet provider. The tool is not installed on Linux systems by default, but is easy to find and install.
In this Linux tip, learn how to use the cat command. It's one of the most basic Linux commands, though it's used for two very different operations and not everyone is likely familiar with the second.
In this Linux tip, learn how to use the blkid command. It gives you a very useful view of block devices on your Linux system. First, it shows the devices (e.g., /dev/sda1). It shows the UUIDs (the 128 bit long "universally unique identifiers") associated with each of them, the block sizes, the file system types and, when available, the PARTUUIDs.
In this Linux tip, learn how to use the ps command. It displays information on running processes. If you want to see only certain processes, you can pass the output of a ps command to grep and specify what you want to see – for example, by username or process name.
In this Linux tip, learn how to use the nmap command. It's generally used for security auditing, but provides interesting and useful information on systems connecting to your local network.
In this Linux tip, learn how to use the more and less commands. They each allow you to browse the content of text files.
In this Linux tip, learn how to use the head and tail commands. They're basic commands that every Linux user should know. The head command is generally used to display the top lines in a text file, and the tail command shows the last lines in a file.
In this Linux tutorial, learn how to use the pi command. You probably won't need it very often, but, if you need to calculate pi to some arbitrary number of digits, you'll probably be surprised at how easy this can be.
In this Linux tip, learn how to use the rig command. It randomly generates name, address and phone number listings. It's useful when you're testing an application and need hundreds or thousands of addresses to make sure that it works correctly.
In this Linux tip, learn how to use the lslogins command. It provides some useful details on user accounts and logins. In its simplest form, you could just type lslogins, but without using sudo, some of the details you'll probably want to see won't be available because the files in which it's stored won't be readable.
In this Linux tip, learn how to use the autoexpect command. You can use it to build expect scripts that let you run scripts without having to provide answers interactively.
In this Linux tip, learn how to use expect. It's a tool that allows you to automate interactions with other scripts so that you can run them with a set of predefined answers.
In this Linux tip, learn how to use the ip neigh command. It works a lot like the arp command, but is considerably newer and still in active development. It provides network details – IP and MAC addresses -- along with an indication of each system's accessibility, but only for systems on your local network.
In this Linux tip, learn how to use the arping command. If it sounds like a combination of arp and ping, that should serve as a hint for how it works. It's a command that you can use to discover or probe systems on your local network.
In this Linux tip, learn how to use the pidof and pgrep commands. Both help you to find the process IDs (PIDs) of running processes. All you have to do is enter the command followed by the name of the process you're interested in.
In this Linux tip, learn how to use the screenfetch and neofetch commands. They're actually both bash scripts that you'll need to install if you haven't already. Once installed, without anything more than invoking them by name, either one will fetch important information from your system and display it alongside an ASCII representation of your Linux distribution's logo.
In this Linux tip, learn how to use the groupmod command. It’s a command that allows you to change the name of a user group. It does this by changing the entry in the /etc/group file (the line that connects the group name with the group number) and, thus, the group that shows up when you do a long file listing.
In this Linux tip, learn how to use the usermod command. It’s a command that allows you to make a lot of different changes to user accounts without having to edit configuration files.
In this Linux tip, learn how to use the factor command. It’s not one that you will likely need very often, but it can be very useful when you’re doing math on the command line. It provides the factors for any number you offer as an argument.
In this Linux tip, learn how to use the disown command. It provides a way to detach a process you’re running from your login session so that it isn’t killed (hung up on) when you log out. This means that the process can continue running after you log off.
In this Linux tip, learn how to use ranger. It’s a tool that allows you to easily browse files in a terminal window, but in a much different manner than you normally would on the command line.
In this Linux tip, learn how to use the tar command. It’s used to create (and extract contents from) file archives. The name “tar” stands for “tape archive” though “tape” is rarely part of the equation anymore.
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