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Linux for Production Support Ch 22 / 32 Beginner 🪟 Windows → Linux

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Vijay installs software without an installer wizard

apt, yum, pip — package management for Windows engineers

⏱ 11 min 6 commands 5 takeaways

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In this chapter

Vijay

Windows engineer, week 6 on Linux

The story

Vijay had been on Linux for 5 weeks. He knew the basics. But every time he needed to install something, he froze. On Windows the answer was always the same: find the website, download the .exe or .msi, double-click, click Next a few times, done. On Linux his colleagues just typed one line and the software appeared.

PACKAGE MANAGERS — THE LINUX APP STORE

A package manager installs, updates, and removes software. It handles all dependencies automatically. You never visit a website to download software.

Two major package managers:

- apt — Ubuntu, Debian, Linux Mint

- yum / dnf — CentOS, RHEL, Amazon Linux, Fedora

Which one do you have?

cat /etc/os-release         # see your Linux distribution
# Ubuntu/Debian: use apt
# CentOS/RHEL/Amazon Linux: use yum or dnf

APT — UBUNTU AND DEBIAN SERVERS

# Update the list of available packages (like Windows Update checking for updates):
sudo apt update

# Install a package:
sudo apt install nginx
sudo apt install python3-pip
sudo apt install -y git curl wget unzip  # -y skips the yes/no prompt

# Remove a package:
sudo apt remove nginx           # remove but keep config files
sudo apt purge nginx            # remove AND config files
sudo apt autoremove             # remove packages no longer needed

# Search for a package:
apt search nginx
apt-cache search "text editor"

# See info about a package:
apt show nginx                  # version, description, dependencies

# List installed packages:
dpkg -l                         # all installed packages
dpkg -l | grep nginx            # is nginx installed?
dpkg -l | wc -l                 # how many packages installed?

# Upgrade all packages (like Windows Update install all):
sudo apt update && sudo apt upgrade -y

# Upgrade everything including kernel:
sudo apt update && sudo apt full-upgrade -y

YUM / DNF — CENTOS AND RHEL SERVERS

sudo yum install nginx          # install
sudo yum remove nginx           # remove
sudo yum search nginx           # search
sudo yum info nginx             # package info
sudo yum update                 # update all packages
sudo yum list installed         # list installed packages
sudo yum list installed | grep nginx    # is nginx installed?

# dnf is the modern replacement for yum (same commands):
sudo dnf install nginx
sudo dnf update

INSTALLING THINGS NOT IN THE PACKAGE MANAGER

Sometimes a package is not in the default repositories. Three approaches:

Approach 1: Add a repository

# Example: adding NodeJS official repository
curl -fsSL https://deb.nodesource.com/setup_20.x | sudo bash -
sudo apt install nodejs

# Example: adding Docker's official repository
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker.gpg
echo "deb [signed-by=/usr/share/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list
sudo apt update
sudo apt install docker-ce

Approach 2: Download a .deb or .rpm file directly

wget https://example.com/software.deb
sudo dpkg -i software.deb      # install .deb (Ubuntu/Debian)
sudo rpm -i software.rpm       # install .rpm (CentOS/RHEL)

Approach 3: Download a binary directly

wget https://example.com/mytool-linux-amd64
chmod +x mytool-linux-amd64
sudo mv mytool-linux-amd64 /usr/local/bin/mytool
mytool --version               # now available as a command

PYTHON PACKAGES — PIP

pip3 install requests           # install a Python package
pip3 install -r requirements.txt  # install from requirements file
pip3 list                       # list installed packages
pip3 show requests              # info about a package

# Virtual environment (isolate dependencies per project):
python3 -m venv myenv           # create virtual environment
source myenv/bin/activate       # activate it
pip3 install requests           # installs only in this env
deactivate                      # back to system Python

WHICH VERSION IS INSTALLED?

nginx -v                        # nginx version
python3 --version               # Python version
node --version                  # Node.js version
git --version                   # git version
java -version                   # Java version
dpkg -l nginx | grep nginx      # full installed version from package manager

FINDING WHERE A PACKAGE INSTALLED ITS FILES

dpkg -L nginx                   # list all files installed by nginx package
which nginx                     # where is the nginx executable?
whereis nginx                   # all locations: binary, config, man page

Vijay's takeaway after learning package management: apt install is faster than finding a download link, running an installer wizard, and clicking through licence screens. One command. Done. Every time.

Key takeaways

apt install name replaces downloading an .exe and running a wizard — one command installs software and all dependencies

sudo apt update first, then sudo apt install — update updates the package list, install actually installs

dpkg -l | grep name checks if a package is installed — faster than opening Programs and Features

apt purge removes software AND its config files — apt remove keeps configs in case you reinstall

python3 -m venv creates an isolated Python environment — equivalent to having separate software installs per project

Commands from this chapter

$ sudo apt update && sudo apt install -y nginx

Update package list then install nginx

$ dpkg -l | grep nginx

Check if nginx is installed — like Programs and Features search

$ apt search 'text editor'

Search for packages by keyword

$ sudo apt purge nginx && sudo apt autoremove

Remove nginx and clean up unused dependencies

$ which nginx && nginx -v

Find where nginx installed and check its version

$ pip3 install -r requirements.txt

Install Python dependencies from requirements file