One of the questions I get from students most often is: what are some good commands to learn on Linux?
It took me a long time to learn Linux commands (along with tmux, ssh, vim, pgp and many other programs). Now I would recommend learning the command line by exercise because that saves a lot of your time.
While there are many different answers to this question, here are some that I recommend to all new users.
date - show the current date. Always good to know
pwd - When you're connected to a server via ssh and want to make sure you know exactly where you are, pwd (print working directory) lets you view the directory you are currently located in.
cd - change directory, files are organized into directories starting from the root
ls - You're probably familiar with this command in other operating systems. Simply put, ls(short for list) is used to show the contents of a directory or if run at the command line, the contents of your current directory.
./program - start program
cat - displays the contents of a file.
As a linux user, you may frequently use the command line to accomplish tasks. The command line lets you do things very quickly.
Sometimes you might need to do something simple, like open a file in your text editor of choice. Learn vim because it's a very powerful editor
Other times, you might be crafting complex commands that automate a specific task. There are many linux commands.