Shell

1 Basic information

Shell is a program where users type commands, and directly interact with system. It is usually done through command line interface (CLI). And, it’s also scripting language just like Python or Java.

Typically uses $ as prompt, followed by a text cursor, and some word to indicate an executable binary:

$ ls # This is a built-in command/binary for Bash shells

Most shells present in different OS are:

• Powershell in Windows
• Zsh in MacOS
• Bash in Linux

2 Frequently used commands

2.1 Navigating Files and Directories

• pwd: prints current working directory
• ls: list files in current directory (by default), accepts optional argument
• cd: change working directory

2.2 Others:

• du -sh <path_of_dir> : show size of a directory