Backend developers spend a lot of time in a terminal. You use it to start your server, install packages, run tests, connect to a database and read logs when something goes wrong in production. Job adverts rarely say "command line" on its own, but they assume it whenever they mention Linux, deployment, Docker or cloud work.
What the command line is
A terminal is a text window where you type a command and press Enter. A program called a shell reads your command, runs it and prints the result. On Linux and Mac the shell is usually Bash or Zsh. On Windows, Git Bash gives you the same commands. On an Android phone, a free app such as Termux gives you a real Linux style shell, which is enough to practise everything in this lesson.
Finding your way around
Files live in folders (also called directories) arranged like a tree. These commands move you around it:
pwd # where am I?
ls # what is here?
cd shop # go into the shop folder
cd .. # go up one level
mkdir logs # make a new folderWorking with files
touch notes.txt # create an empty file
cat notes.txt # print a file
cp a.txt b.txt # copy
mv b.txt old.txt # rename or move
rm old.txt # delete, with no recycle binBe careful with rm. There is no undo.