Guide to common terminal commands

This guide covers a selection of essential terminal commands used on both macOS and Linux systems.

Introduction to the terminal

The terminal provides a command line interface (CLI) where users can type commands to perform operations without a graphical user interface (GUI). macOS terminal commands and Linux terminal commands are often very similar because both systems are Unix-based.

Basic terminal commands

1. Navigating the file system

• pwd (print working directory): Displays the path of the current directory you are in.

• cd <directory> (change directory): Changes the current directory to <directory>. Use cd .. to go up one directory level or cd to return to the home directory.

• ls (list): Lists all files and directories in the current directory. Use ls -l for detailed information and ls -a to show hidden files.

2. File management

• touch <filename>: Creates a new empty file named <filename>.

• mkdir <directory> (make directory): Creates a new directory named <directory>.

• cp <source> <destination> (copy): Copies files or directories from <source> to <destination>.

• mv <source> <destination> (move): Moves files or directories from <source> to <destination>. Also used for renaming.

• rm <filename> (remove): Deletes a file. Use rm -r <directory> to delete a directory and all its contents.

3. System monitoring and management

• top: Displays an ongoing view of process activity. It provides a dynamic real-time view of a running system. Equivalent to htop on Linux for an enhanced view.

• df (disk free): Shows the amount of disk space available on the file system containing each file name argument.

• du (disk usage): Displays the disk usage for the directory you specify. By using du -sh, you can see a summary of the disk space used by each directory.

• kill <PID> (kill process): Terminates the process with the specified Process ID (PID).

4. Networking

• ping <hostname>: Checks the network connection to a host. It sends ICMP ECHO_REQUEST packets to network hosts.

• netstat: Displays network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.

• ifconfig: Used to configure the kernel-resident network interfaces. It is used at boot time to set up interfaces as necessary.

• curl <URL>: Transfers data from or to a server, using one of the supported protocols (HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, DICT, TELNET, LDAP or FILE).

Advanced commands

• grep <pattern> <file>: Searches for the pattern in the file and outputs the matching lines. Very useful for searching through logs or files.

• chmod <permissions> <file>: Changes the file mode (permissions) of a file or directory.

• chown <user>:<group> <file>: Changes the owner and group of a file or directory.

• sudo <command>: Executes a command with superuser privileges, necessary for commands that require administrative permissions.

Tips for using the terminal

• Combine commands: Use pipes (|) and redirections (>, >>) to combine multiple commands.
• Scripting: Bash scripting can automate repetitive tasks and combine many commands into one script.
• Customize your environment: Use .bashrc or .bash_profile to customize your shell, setting up aliases and shortcuts for common commands.