Opening the Terminal on Your Mac
It is already there. You do not need to install anything. Open Applications/Utilities/Terminal.app or press Cmd+Space and type "terminal." When it opens you are looking at a zsh shell, Apple switched from bash to zsh back in Catalina. That is your first adjustment if you learned Unix on something else. The prompt will say something like yourusername@hostname where the default is your Mac username and the hostname is derived from your machine name. Type uname -a and press enter. You will see Darwin version numbers, which is the Unix foundation macOS is built on. It is POSIX compliant. It passes the Single UNIX Specification. The rest of the system is just layers on top of that. I have been running macOS as my primary workstation since Tiger, and the Unix side has changed in quiet ways that trip people up constantly. The core commands are the same commands you see on any Linux distro, but the filesystem layout and the toolchain have a few macOS-specific quirks. One thing that catches almost everyone off guard is the APFS filesystem and how macOS manages volumes. If you run mount or df -h you will see a lot of synthetic mount points. Things like /System/Volumes/Data and / being separate mounts. They look like a problem if you assume a traditional single-root filesystem. They are not a problem. They are Apple's implementation of APFS volume separation, and you should just get used to it. Another thing nobody warns you about is SIP. System Integrity Protection locks down /System, /usr, and several other directories. You cannot just install something into those paths even with sudo, because SIP will block it. I spent about forty minutes trying to figure out why a Python package would not install into /usr/local on a fresh macOS install. It turned out I had Homebrew installed but the path precedence was wrong because SIP was also redirecting some writes. The fix was checking csrutil status and making sure my PATH in .zshrc included /opt/homebrew/bin or /usr/local/bin before the system paths. That single change fixed everything.
Package Management: Homebrew Is Not Optional
You are going to need a package manager. The system tools cover basic Unix, but the moment you want something like ripgrep, tmux, ffmpeg, or a newer version of Python, you are on your own without it. Homebrew is the standard. Install it by pasting the installation command from brew.sh into your terminal. Do not second guess the script. It is benign. After installation, you will notice the binary paths differ depending on your chip. On Intel Macs Homebrew installs to /usr/local. On Apple Silicon it installs to /opt/homebrew. If you are following along and commands are missing, check which path your shell is using. which git and echo $PATH will tell you immediately whether you are pulling the Homebrew version or the system version. This matters more than most people realize. The system Python on macOS is still version 3.9 in many configurations because Apple does not ship a bleeding edge toolchain. Homebrew gives you 3.12 or newer within a minute. brew install python followed by python3 --version will confirm it. If you then run into issues where your IDE is still pointing at the system Python, that is a configuration problem, not a Homebrew problem. Set your IDE's interpreter path explicitly and move on.
SSH And Remote Access
macOS includes ssh, scp, sftp, and rsync out of the box. If you are moving between machines regularly, configure your SSH keys immediately. Generate one with ssh-keygen -t ed25519 -C "your@email.com". Ed25519 keys are shorter and faster than RSA. Copy the public key to your remote server with ssh-copy-id user@host. If that command is not available on your remote server, fall back to cat ~/.ssh/id_ed25519.pub | ssh user@host "mkdir -p ~/.ssh && cat >> ~/.ssh/authorized_keys". It is clunky but it works everywhere. Set up a ~/.ssh/config file. I have entries for every server I touch regularly, and each entry specifies the hostname, the user, the identity file, and whether to use agent forwarding. Without this file you will be typing long commands repeatedly. With it you just type ssh webserver and you are in. A realistic detail here: if you ever connect to a server and get a "host key verification failed" error, do not blindly accept the new key. That usually means the server was reimaged or the key was rotated, but it can also mean a man in the middle is active. Check with the server owner first, then remove the old key with ssh-keygen -R hostname and try again.
Get the Full Details
The Filesystem Beyond Your Home Directory
Your home directory is in /Users/yourusername. Everything else is managed differently than on Linux. The /Applications directory holds app bundles, not individual binaries. The actual binaries are buried inside them or in /usr/bin, which is the BSD-derived toolchain. /usr/local is for manually compiled software or Homebrew on Intel. /opt/homebrew is for Homebrew on Apple Silicon. /Library holds system-wide preferences and support files, while /System is completely sealed by SIP. If you are transferring files from a Linux or Windows machine, pay attention to case sensitivity. macOS filesystems are case-insensitive by default. If you have a project with both README.md and readme.md, it will not crash your system, but Git will behave strangely. I ran into this exact issue when pulling a repository from a Linux server onto an M-series Mac. The working tree showed no changes because the filesystem treated the two filenames as identical. The workaround was running git config core.ignorecase false in that repository, which forced Git to respect actual filename differences. This setting is local to the repo, so you do not break anything globally.
Permissions And Sudo
sudo works like it does everywhere else. Type sudo ls /root and it will prompt for your password. The important thing to understand is that macOS does not use a root account by default. Your admin account has sudo privileges, but the root user is locked. You can enable it with dsenableroot but you should not, unless you have a very specific reason. Most admin tasks do not require the root account. sudo is sufficient and safer because it leaves an audit trail in /var/log/system.log. File permissions on macOS follow the standard Unix model: owner, group, others. ls -la shows them. The sticky bit appears occasionally on shared directories. Extended attributes and ACLs are where things get different. macOS uses extended attributes heavily for things like quarantine flags on downloaded files. If you try to copy a file from a downloaded app and run it, Gatekeeper will block it. Remove the quarantine attribute with xattr -d com.apple.quarantine /path/to/app if you trust the source. This is a common step when working with command line tools downloaded from the internet.
Process Management And Logging
Use ps aux to see running processes. top gives you a real-time view, though htop from Homebrew is significantly more readable. kill -9 is the nuclear option. Use kill (which sends SIGTERM) first. Most processes will clean up after a SIGTERM. If they do not respond within ten seconds, then escalate to kill -9. Logs live in /var/log and /Library/Logs. The system log is also accessible through log show and log stream, which are better than tailing raw log files. Try log show --predicate 'eventMessage contains "error"' --last 1h to see recent errors. If your Mac is acting weird, this command usually surfaces the relevant information within seconds. I used this exact approach when diagnosing a persistent Wi-Fi drop issue on a 2021 MacBook Pro. The log showed repeated authentication failures with the router, which pointed directly to a DNS misconfiguration rather than a hardware problem. Ten minutes of log analysis saved me from replacing a perfectly functional machine.
Shell Configuration
Your shell reads .zshrc on startup. Put your aliases, functions, and environment variables there. Here is a minimal but practical setup that handles most daily needs: alias ll="ls -la"alias gs="git status"alias grep="grep --color=auto"export PATH="/opt/homebrew/bin:/usr/local/bin:$PATH" Replace the Homebrew path segment with /usr/local/bin if you are on Intel. After editing .zshrc, run source ~/.zshrc to apply changes without reopening the terminal. If you want tab completion and syntax highlighting, install zsh-autosuggestions and zsh-syntax-highlighting from Homebrew and add the sourced lines to your config. These two plugins alone reduce typo-related errors by a significant margin. I go through maybe one mis-typed command per week now instead of several per session.
What Unix On macOS Still Cannot Do
Do not expect full Linux compatibility. Some tools simply do not compile on Darwin. nftables does not exist. systemd is not present. Init is launchd, and it uses plist files instead of service units. If you are migrating a Linux deployment script, rewrite the service management parts for launchd. There are conversion tools like launchctl generators, but they are imperfect. The kernel itself is Darwin, which is a hybrid kernel, not a monolithic one like Linux. This means some kernel-level diagnostics you might rely on are not available. dmesg exists but works differently. Use log show --predicate 'subsystem == "com.apple.kernel"' instead for kernel messages. Another limitation: macOS does not support namespaces or cgroups in the same way Linux does. Docker runs on macOS through a Linux virtual machine, not natively. If you need container-native features like cgroup memory limits or full namespace isolation, you are working through a translation layer. It works for most development purposes but falls apart for low-level systems programming that depends on direct kernel interaction. In those cases you need a real Linux VM or a cloud instance. The Unix on your Mac is capable. It is mature. It will handle development, scripting, networking, and system administration tasks without complaint. It is not Linux, and treating it as Linux will cause friction. Learn the differences early, configure your shell properly, and use Homebrew for anything the base system does not provide. That is the practical path.
