The Unix shell is a command-line environment for interacting with your operating system, typically macOS or Linux.

It allows you to launch programs, manage files, and much more, all through a terminal interface.

Instead of clicking around with a mouse, the shell lets you tell your computer what to do by typing words and commands.

This document touches on the basics of:

• Navigating directories
• Working with files
• Viewing file content
• And useful tips and tricks

In the Unix shell, you often need to move around between different folders (called directories) to work with your files.

Some basic commands help you check where you are, list files, and change your location in the filesystem.

The command above prints the current working directory, showing you the path to your current folder.

This lists all files and folders in the current directory. You can add options to show more details.

• cd foldername - change into a specific folder
• cd .. - go up one level to the parent directory
• ls -l - list files in long format with details
• ls -a - show hidden files and folders

These commands are the foundation for moving around and managing files from the command line.

The Unix shell lets you create, view, copy, move, and delete files quickly using commands.

Instead of using a graphical interface which you may be used to, you can type commands to handle files right from the terminal.

This creates an empty file called newfile.txt if it doesn't already exist.

This copies file1.txt to a new file called file2.txt.

This moves file1.txt into the Documents directory. It can also rename files if you provide a new name.

• rm filename - delete a file
• cat filename - print file contents to the terminal
• nano filename - open a file for editing in a terminal text editor
• cp -r folder1 folder2 - copy entire folders
• mv oldname.txt newname.txt - rename a file

Using these commands, you can quickly manage many files without leaving the command line.

The Unix shell provides many commands to look inside files without opening them in a full editor.

This is useful for quickly checking logs, configuration files, or code.

This prints the entire contents of a file directly in the terminal.

This opens a file in a scrollable viewer so you can move up and down easily.

Displays just the first few lines of a file, useful for a quick peek.

Shows the last few lines of a file, helpful for checking logs.

• tail -f filename - watch new lines appear in a growing file like logs
• less +F filename - view a file and follow new changes like a live log viewer
• head -n 20 filename - show the first 20 lines of a file
• cat file1 file2 - display multiple files at once
• less -N filename - view a file with line numbers

These commands make it quick and easy to read file contents directly from the command line.

Besides basic commands, the Unix shell has many small features and shortcuts that can make your work much faster and easier.

One of the most helpful tools is tab completion. When typing a file or folder name, you can press the Tab key to automatically complete it or show suggestions.

Pressing Tab after typing Doc might complete it to Documents/ if that folder exists.

Here are some other useful tips for working in the shell:

• Use the up and down arrow keys to scroll through your recent commands instead of typing them again.
• Type history to see a list of past commands.
• Press Ctrl + C to stop a running command.
• Use clear to clear your terminal screen.
• Use .. to move up one directory level, e.g. cd ..
• Use man command to read the manual page and learn how a command works.

Practicing these small shortcuts helps make using the shell feel much faster and more comfortable.