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How to use the free command in a terminal?

by travis•

Hey there! I’m a rep from a terminal supplier, and I’m stoked to chat about one of the handiest commands in the terminal world: the free command. Whether you’re a seasoned tech whiz or just starting to dip your toes into the terminal waters, this command is super useful. So, let’s dive right in! Terminal

What the Heck is the free Command?

The free command is like a little window into your system’s memory usage. It gives you a quick snapshot of how much RAM your computer is using, how much is free, and how much is being used for buffers and caches. This info is crucial for keeping an eye on your system’s performance and making sure it’s running smoothly.

When you run the free command in your terminal, you’ll see a table with a bunch of numbers. At first glance, it might look a bit confusing, but don’t worry – I’ll break it down for you.

Here’s a typical output of the free command:

              total        used        free      shared  buff/cache   available
Mem:        8161344     2123260     4418848       44872     1619236     5616068
Swap:       2097148           0     2097148

Let’s go through each column and see what it means:

  • total: This is the total amount of physical memory (RAM) your system has. In the example above, the system has 8,161,344 kilobytes (or about 8GB) of RAM.
  • used: This is the amount of RAM that’s currently being used by your system. In the example, 2,123,260 kilobytes are being used.
  • free: This is the amount of RAM that’s currently available for use. Here, 4,418,848 kilobytes are free.
  • shared: This is the amount of RAM that’s being shared between multiple processes. In the example, 44,872 kilobytes are being shared.
  • buff/cache: This is the amount of RAM that’s being used for buffers and caches. Buffers are used to temporarily store data that’s being read from or written to disk, while caches are used to store frequently accessed data in memory. In the example, 1,619,236 kilobytes are being used for buffers and caches.
  • available: This is the estimated amount of RAM that’s available for starting new applications, without swapping. In the example, 5,616,068 kilobytes are available.

The Swap section at the bottom shows information about your system’s swap space. Swap space is a portion of your hard drive that’s used as an extension of your system’s RAM. If your system runs out of physical RAM, it can start using swap space to store data. In the example, the system has 2,097,148 kilobytes (or about 2GB) of swap space, and none of it is currently being used.

How to Use the free Command

Using the free command is as easy as pie. All you have to do is open up your terminal and type free and hit Enter. That’s it! You’ll instantly get a snapshot of your system’s memory usage.

But the free command also has a bunch of options that you can use to customize the output. Here are some of the most useful ones:

  • -h or --human-readable: This option makes the output easier to read by displaying the memory sizes in a more human-friendly format, like kilobytes (K), megabytes (M), or gigabytes (G). For example, if you run free -h, you’ll get output like this:
              total        used        free      shared  buff/cache   available
Mem:           7.8G        2.0G        4.2G         44M        1.6G        5.4G
Swap:          2.0G          0B        2.0G
  • -t or --total: This option adds a line at the bottom of the output that shows the total memory usage, including both physical RAM and swap space. For example, if you run free -t, you’ll get output like this:
              total        used        free      shared  buff/cache   available
Mem:        8161344     2123260     4418848       44872     1619236     5616068
Swap:       2097148           0     2097148
Total:     10258492     2123260     6515996       44872     1619236     5616068
  • -s or --seconds <interval>: This option makes the free command run continuously, displaying the memory usage at the specified interval (in seconds). For example, if you run free -s 5, the command will display the memory usage every 5 seconds. To stop the command, just press Ctrl+C.

Why You Should Care About the free Command

So, why is the free command so important? Well, for starters, it can help you diagnose performance issues on your system. If you notice that your system is running slow, you can use the free command to see if it’s because your system is running out of memory. If the used column is close to the total column, it means your system is using most of its available RAM, and you might need to close some applications or add more RAM to your system.

The free command can also help you optimize your system’s performance. By monitoring the buff/cache column, you can see how much of your system’s RAM is being used for buffers and caches. If this number is very high, it means your system is caching a lot of data, which can improve performance. However, if your system is running low on memory, you might want to flush the buffers and caches to free up some RAM. You can do this by running the following command:

sudo sync && sudo echo 3 > /proc/sys/vm/drop_caches

Our Terminals and the free Command

As a terminal supplier, we understand the importance of having a reliable and efficient terminal that can handle all your memory monitoring needs. Our terminals are designed to be fast, responsive, and easy to use, making them the perfect choice for anyone who needs to keep an eye on their system’s memory usage.

Whether you’re a system administrator, a developer, or just someone who wants to keep their system running smoothly, our terminals are the perfect tool for the job. With our terminals, you can easily run the free command and other memory monitoring tools, giving you the information you need to make informed decisions about your system’s performance.

Let’s Chat!

2.54mm Pitch Connectors If you’re interested in learning more about our terminals or how they can help you monitor your system’s memory usage, we’d love to hear from you. Whether you have questions, need a demo, or are ready to place an order, we’re here to help. Just reach out to us, and we’ll get back to you as soon as possible. Let’s work together to make your terminal experience the best it can be!

References

  • "Linux Command Line Bible" by Richard Blum and Christine Bresnahan
  • "The Linux Documentation Project" for general Linux knowledge and command reference.

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