# Installing Tools: Homebrew and apt

A package manager is an app store you type to; on Ubuntu it's apt, which needs sudo to install, and on a Mac it's Homebrew's brew, which doesn't, and both search, install, update and remove tools by name.

Apprentice · Unix · Linux · Updated November 10, 2026

## After this lesson you can

- Find a tool's package and check whether it's installed with apt search and apt-cache policy, or brew search and brew info
- Install, update and remove tools with sudo apt or with brew, and tell apt update from apt upgrade

## Key takeaways

- A package manager installs programs by name from a catalog its makers check. Ubuntu and WSL use apt; a Mac uses Homebrew, typed brew.
- apt search and apt-cache policy look things up and change nothing. brew search and brew info do the same on a Mac.
- sudo apt install name installs a tool, and sudo apt remove name removes it. On a Mac it's brew install and brew uninstall, never with sudo.
- apt update only refreshes the catalog. apt upgrade installs the newer versions. Run them in that order; brew update and brew upgrade work the same way.

A tutorial says "run `tree` to see the project's folders", and your terminal says this:

```bash
tree
```

```text
Command 'tree' not found, but can be installed with:
sudo snap install tree  # version 2.1.3+pkg-5852, or
sudo apt  install tree  # version 2.3.1-1
See 'snap info tree' for additional versions.
```

The program isn't on your computer yet. You could search the web for it, find a download page, and hope it's the real one. Or you can ask your computer's **package manager**: an app store you type to. Developers get nearly every tool this way, and IT administrators set up whole servers with it, one line per program.

## An app store you type to

A phone's app store has a catalog, installs an app by name, keeps every app up to date, and removes one cleanly. A package manager does the same for the terminal. Each program comes as a **package**, and the catalog lists thousands of them, checked by the people who look after the store.

- **Ubuntu**, and Ubuntu in WSL on Windows, use **apt**. In WSL, apt installs into Ubuntu, not into Windows.
- **A Mac** uses **Homebrew**, typed `brew`, which *Setup: The Terminal on a Mac* installed.

The `tree` message above offers a second store, snap, which Ubuntu also has. This course uses apt.

## Look before you install

Searching changes nothing, so it needs no password. `apt search` looks through the catalog's names and descriptions. A short word like `jq` matches hundreds of descriptions, so `--names-only` with `'^jq$'` (a name that is exactly jq, as in *Patterns: Regular Expressions for grep*) finds the one:

```bash
apt search --names-only '^jq$'
```

```text
jq/resolute-updates,resolute-security 1.8.1-4ubuntu2 amd64
  lightweight and flexible command-line JSON processor
```

The package's name, where it comes from (`resolute` is Ubuntu 26.04's code name; yours shows your version's), its version, and a line saying what it does. `apt-cache policy` says whether a package is installed, and which version you'd get:

```bash
apt-cache policy tree
```

```text
tree:
  Installed: (none)
  Candidate: 2.3.1-1
  Version table:
     2.3.1-1 500
        500 http://archive.ubuntu.com/ubuntu resolute/universe amd64 Packages
```

`Installed: (none)` means not yet, and `Candidate` is the version `apt install` would bring. For something you already have, both lines show a version:

```bash
apt-cache policy bash | head -n 3
```

```text
bash:
  Installed: 5.3-2ubuntu1
  Candidate: 5.3-2ubuntu1
```

On a Mac, `brew search tree` and `brew info tree` do the same jobs.

## Install, update, remove

Installing changes the whole computer, not only your files, so apt needs the administrator's permission: `sudo` (*sudo and Who Owns a File*), and your password. These lines change your computer, so read them before you run them:

```bash
sudo apt update
sudo apt install tree
```

`apt update` refreshes apt's catalog, so it knows the newest versions; it installs nothing. `apt install tree` downloads tree and sets it up, and if apt asks whether to continue, press Y, then Enter. Now `tree` draws the folder you're in as a tree, with lines joining each folder to what's inside it.

To bring everything you've installed up to date, refresh the catalog, then upgrade. To take a tool away again, remove it:

```bash
sudo apt update
sudo apt upgrade
sudo apt remove tree
```

| Job | Ubuntu (apt) | A Mac (Homebrew) |
|---|---|---|
| Find it | `apt search name` | `brew search name` |
| Is it installed? | `apt-cache policy name` | `brew info name` |
| Install it | `sudo apt install name` | `brew install name` |
| Refresh the catalog | `sudo apt update` | `brew update` |
| Install newer versions | `sudo apt upgrade` | `brew upgrade` |
| Remove it | `sudo apt remove name` | `brew uninstall name` |

Never put `sudo` in front of `brew`. Homebrew installs into a folder your own account owns, so it needs no administrator, and it's built to refuse to run as one.

## Four tools worth having

- **tree** draws a folder and everything inside it as a tree.
- **htop** shows what your computer is busy with, live, like a task manager: press **q** to quit.
- **jq** reads and reshapes JSON, the text format most websites' data travels in.
- **tldr** gives short, everyday examples for a command, where `man` gives the whole manual: `tldr tar` shows a handful of the ways people use `tar` most often. Its package is called **tealdeer**. The first time, run `tldr --update` so it downloads its pages.

One line installs all four, on Ubuntu or on a Mac:

```bash
sudo apt install tree htop jq tealdeer
brew install tree htop jq tealdeer
```

Run only the line for your computer. Then check one with `tree --version`: it prints its version, and `command not found` is gone.

## Check yourself

2 questions to try on the lesson page.

## So what

When a tutorial needs a tool you don't have, you're one line away: search for it, check it, install it, and keep everything up to date with two commands.

## Key terms

- [Package Manager](https://www.ask-codey.com/glossary/package-manager)
- [apt](https://www.ask-codey.com/glossary/apt)
- [Homebrew](https://www.ask-codey.com/glossary/homebrew)
- [sudo](https://www.ask-codey.com/glossary/sudo)
- [top and htop](https://www.ask-codey.com/glossary/top-and-htop)

## Cheat sheets

- [Installing Tools: Homebrew and apt](https://www.ask-codey.com/cheat-sheets/bash-installing-tools-cheat-sheet)

## Related

- [Setup: The Terminal on Linux](https://www.ask-codey.com/lessons/bash-setup-linux)
- [Setup: The Terminal on a Mac](https://www.ask-codey.com/lessons/bash-setup-macos)
- [sudo and Who Owns a File](https://www.ask-codey.com/lessons/bash-sudo-and-ownership)

Source: https://www.ask-codey.com/lessons/bash-installing-tools