This page is under construction, please feel free to add a relevant section or subpage, For now I just need to mention homebrew because it's the preferred method for getting Meld.
The default app providing a CLI on macOS is Terminal. It's located in /Applications/Utilities/Terminal.app
if you're looking for it in Finder, but the simplest way to get to it is to:
Term
Terminal
app as a top search resultTerminal
search resultHomebrew is a package manager for macOS. Pretty much any developer software made for Linux (and much that's not) is available for install via Homebrew, and this installation is typically much simpler than alternatives, especially for developer tools.
Both installing Homebrew itself, as well as afterward using it to install other software are done via the command line.
On the command line, paste the command found at https://brew.sh/#install to install homebrew.
To install a package that's command-line-only, simply run:
brew install <package>
brew install lolcat
To install a package that has a graphical user interface, simply run:
brew install --cask <package>
brew install --cask meld