Mac & Terminal fixes, run on a real Mac before we publish.

Undo git add with git restore --staged <file>, or git reset to unstage everything. Your edits stay. Tested on Mac, incl. repos with no commits yet.

Run system_profiler SPHardwareDataType to see your MacBook's chip, cores, and RAM. One ioreg line also prints the model year. Tested on macOS Tahoe.

Run networksetup -getmacaddress en0 for your Mac's real Wi-Fi MAC address. ifconfig shows the private one instead. Tested on macOS Tahoe.

Measure ~/Library/Caches with du, quit the app, then delete only its cache folder. Tested on macOS Tahoe: Homebrew, npm, pip, Chrome and the hidden cache.

Run sudo shutdown -r now to restart a Mac from Terminal. Tested on macOS Tahoe: shutdown timers, cancelling, the osascript way and why pmset can't restart.

Run find . -name "file.txt" to search the current folder and subfolders, or mdfind -name to search the Spotlight index. Tested on macOS Tahoe with zsh.

Run touch notes.txt to create an empty file in Mac Terminal, or echo "text" > file.txt to create one with content. Tested on macOS Tahoe with zsh.

Run brew install python to get the latest Python 3 on Mac. Tested: which version you get, why python3.12 has no python3 link, and the 3.9 system Python.

Run sw_vers -productVersion to print your macOS version in Terminal. Tested on macOS Tahoe: build number, Darwin kernel, arm64 vs x86 and script-safe checks.

Run open . to open the current Terminal folder in Finder, or open -R file to reveal a file. Tested on macOS Tahoe with spaces, symlinks and .app folders.

macOS has no timeout command. Install coreutils for gtimeout, or use perl -e 'alarm shift; exec @ARGV' 5 cmd with no install. Tested on macOS Tahoe.

Run brew uninstall <name>, then brew autoremove to drop unused dependencies and brew cleanup --prune=all to clear the download cache. Tested on macOS Tahoe.

Check MacBook battery health in System Settings > Battery, or run system_profiler SPPowerDataType for cycle count, condition and maximum capacity.

Run ssh-keygen -t ed25519 -C "you@example.com", save the passphrase in Keychain, copy the key with pbcopy and add it to GitHub. Tested on macOS 26.

Find large files on a Mac with find ~ -xdev -type f -size +1G, or instantly with mdfind. Tested timings, du sizing, and what is safe to delete.

See what is using RAM on a Mac with top -l 1 -o mem, memory_pressure and vm_stat. Tested on Apple Silicon, with swap, compression and GB conversion.

Run caffeinate -d to keep your Mac's screen on until you press Ctrl+C, or caffeinate -d -t 3600 for one hour. Every flag tested on macOS Tahoe.

Find what is using a port with lsof -nP -iTCP:8080 -sTCP:LISTEN, then kill it by PID. Plus why ports 5000 and 7000 are taken by AirPlay on macOS.

Flush DNS on macOS Tahoe with: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder. Then check it worked, and see when flushing won't help.

Add export MY_VAR=value to ~/.zshrc (or ~/.zprofile for PATH), then run source ~/.zshrc. Tested on macOS Tahoe with zsh 5.9, plus the temporary way.

Run ipconfig getifaddr en0 to get your Mac's local IP, and curl -4 -s https://ifconfig.me for your public IP. Tested on macOS Tahoe with real output.

Undo the last Git commit and keep your changes with git reset --soft HEAD~1. Tested reset modes, revert, amend, reflog recovery and pushed commits.

Press Cmd+Shift+Period in Finder to show hidden files on Mac. Plus ls -a, the permanent defaults command, and chflags to hide or unhide any file.

On Apple Silicon, Homebrew lives in /opt/homebrew/bin. Add eval "$(/opt/homebrew/bin/brew shellenv)" to ~/.zprofile. Fixes for python, pip, npm and code too.