Salesforce DX offers you an open and standard developer experience, which helps you build application using the tools like Git, Eclipse, Selenium and more. Salesforce DX consists of an updated Eclipse Integrated Development environment (IDE) which expands the value of the toolset to salesforce developers.
In this blog post, I have put together a list of commands which we use very often.

Command to login to New Org and set the org as Default

sfdx force:auth:web:login -d -a DevHub

Command to create an new project

sfdx force:project:create -n Exampleproject

Command to create New scratch org:

sfdx force:org:create -s -f config/project-scratch-def.json -a ExampleScratch

How to pull code:

sfdx force:source:pull

How to push code?

sfdx force:source:push

How to open scratch org?

sfdx force:org:open 

How to generate password for scratch org user?

sfdx force:user:password:generate --targetusrname

If you want to see the password for scratch org user

 sfdx force:user:display -u

I hope you will enjoy this blog post.  Let me know which DX command you have used in the past. Share your thoughts in the comment section.
Resources to learn more