Kubernetes Journey — Basic Linux commands you should know
If you are starting to get into Kubernetes, and don't know basic Linux commands yet, you should probably learn how to walk before you can run. Take my advice and read this blog until you learn these commands, and it will accelerate your learning.
This blog will be short and sweet, lets jump straight into it.
ls
The ls command is used to view the contents of a directory. By default, this command will display the contents of your current working directory.
If you want to see the content of other directories, type ls and then the directory’s path. For example, enter ls /myfolder to view the content of myfolder.
- ls -R will list all the files in the sub-directories as well
- ls -a will show the hidden files
- ls -al will list the files and directories with detailed information like the permissions, size, owner, etc.
clear
The clear command can be used to clear up your terminal screen to give you a blank page.
pwd
Use the pwd command to find out the path of the current working directory you’re in. The command will return an absolute (full) path, which is basically a path of all the directories that starts with a forward slash (/). An example of an absolute path is /users/bmccoy.
mkdir
Use mkdir command to make a new directory — if you type mkdir commands it will create a directory called commands.
- To generate a new directory inside another directory, use this Linux basic command mkdir kubernetes/newfile
cd
To navigate through the Linux files and directories, use the cd command. It requires either the full path or the name of the directory, depending on the current working directory that you’re in.
Let’s say you’re in /users/bmccoy/Development and you want to go to Blog, a subdirectory of Development. To do so, simply type the following command: cd Blog.
There are some shortcuts to help you navigate quickly:
- cd .. to move one directory up
- cd to go straight to the home folder
touch
The touch command allows you to create a blank new file through the Linux command line. As an example, enter touch example.txt to create a txt file. This can be anyfile, eg deployment.yaml
cp
Use the cp command to copy files from the current directory to a different directory. For instance, the command cp example.txt example1.txt would create a copy of example.txt and rename it to example1.txt.
mv
The primary use of the mv command is to move files, although it can also be used to rename files.
The arguments in mv are similar to the cp command. You need to type mv, the file’s name, and the destination’s directory. For example: mv example.txt commands
To rename files, you can do mv example.txt newexample.txt
rm
The rm command is used to delete files and directories. If you only want to delete the directory — as an alternative to rmdir — use rm -r.
cat
cat (short for concatenate) is used to list the contents of a file on the standard output (sdout). To run this command, type cat followed by the file’s name and its extension. For instance: cat svc.yaml.
Here are other ways to use the cat command:
- cat > filename creates a new file
- cat filename1 filename2>filename3 joins two files (1 and 2) and stores the output of them in a new file (3)
find
Similar to the locate command, using find also searches for files and directories. The difference is, you use the find command to locate files within a given directory.
As an example, find /home/ -name svc.yaml command will search for a file called svc.yaml within the home directory and its subdirectories.
history
When you’ve been using Linux for a certain period of time, you’ll quickly notice that you can run hundreds of commands every day. As such, running history command is particularly useful if you want to review the commands you’ve entered before.
grep
Another basic Linux command that is undoubtedly helpful for everyday use is grep. It lets you search through all the text in a given file.
To illustrate, grep king svc.yaml will search for the word kind in the svc file. Lines that contain the searched word will be displayed fully.
echo
This command is used to move some data into a file. For example, if you want to add the text, “Hello, my name is Brad” into a file called name.txt, you would type echo Hello, my name is Brad >> name.txt
sudo
Short for “SuperUser Do”, this command enables you to perform tasks that require administrative or root permissions. However, it is not advisable to use this command for daily use because it might be easy for an error to occur if you did something wrong.
ping
Use the ping command to check your connectivity status to a server. For example, by simply entering ping google.com, the command will check whether you’re able to connect to Google and also measure the response time.
Vi
Using the vi command opens up the vi editor. to exit press esc the type :wq! to save and quit or q! to quit. I will do a seperate blog on this.
Conclusion
Learning these basic commands before you learn Kubernetes will make it much easier to learn. They will also help you with your speed when doing your certs like CKA, CKAD, and CKS. For more blogs and videos you can follow me on twitter here.
