Tag: journalctl

Ubuntu Linux Cheatsheet

The world’s most popular desktop & server Linux
Uses apt (Debian-based). All privileged commands require sudo.
Covers Ubuntu Desktop, Server, LTS, and Snaps.

1. Installation (Live USB / Server ISO)

Task	Command / Action
Boot Live USB	Try Ubuntu → Install Ubuntu
Disk setup	Use Eraser or Something Else (manual: `/`, `/boot`, `swap`)
Server install	Boot ISO → Language → Minimal or Standard
Enable SSH (server)	`sudo apt install openssh-server`
Update on first boot	`sudo apt update && sudo apt upgrade -y`

2. APT (Package Management)

Action	Command
Update package lists	`sudo apt update`
Upgrade all packages	`sudo apt upgrade -y`
Full upgrade (new deps)	`sudo apt full-upgrade -y`
Install package	`sudo apt install package`
Remove package	`sudo apt remove package`
Purge (with config)	`sudo apt purge package`
Autoremove unused	`sudo apt autoremove`
Clean cache	`sudo apt clean`
Search package	`apt search keyword`
List installed	`dpkg -l \| grep ^ii`
Show info	`apt show package`
Fix broken installs	`sudo apt install -f`
Which package owns file	`dpkg -S /path/to/file`

3. Snaps (Universal Packages)

Action	Command
Install snap	`sudo snap install package`
Update all snaps	`sudo snap refresh`
List installed	`snap list`
Remove snap	`sudo snap remove package`
Classic confinement	`sudo snap install --classic code`
Find in store	`snap find keyword`

Common Snaps: code, discord, spotify, slack, postman, chromium

4. System Administration

Task	Command
List services	`systemctl list-unit-files --type=service`
Enable service	`sudo systemctl enable service`
Start service	`sudo systemctl start service`
Status	`systemctl status service`
View logs	`journalctl -u service`
Reboot	`sudo reboot`
Shutdown	`sudo poweroff`
Disk usage	`df -h`
Memory	`free -h`
Processes	`htop` or `top`
Kill process	`kill PID` or `pkill name`
Check Ubuntu version	`lsb_release -a` or `cat /etc/os-release`

5. Users & Permissions

Action	Command
Add user	`sudo adduser username`
Add to sudo group	`sudo usermod -aG sudo username`
Change password	`sudo passwd username`
Change owner	`sudo chown user:group file`
Change permissions	`chmod 755 file`
Switch user	`su - username`

6. Networking

Task	Command
Check IP	`ip a` or `nmcli device show`
List Wi-Fi	`nmcli device wifi list`
Connect Wi-Fi	`nmcli device wifi connect SSID password "pass"`
Restart NetworkManager	`sudo systemctl restart NetworkManager`
Check DNS	`cat /etc/resolv.conf`
Test connection	`ping -c 4 google.com`
Firewall (UFW)	`sudo ufw status` `sudo ufw allow 22/tcp` `sudo ufw enable`

7. Filesystem & Storage

Task	Command
Mount USB	`sudo mount /dev/sdb1 /mnt/usb`
Unmount	`sudo umount /mnt/usb`
Format ext4	`sudo mkfs.ext4 /dev/sdX1`
Check disk	`sudo fsck /dev/sdX1`
Find large files	`du -ah / \| sort -rh \| head -n 20`
Search files	`find / -name "filename" 2>/dev/null`
Disk analyzer (GUI)	`baobab`

8. Server-Specific

Service	Install & Enable
LAMP Stack	`sudo apt install apache2 mysql-server php libapache2-mod-php`
Nginx + PHP	`sudo apt install nginx php-fpm`
Docker	`sudo apt install docker.io` `sudo usermod -aG docker $USER`
Node.js	`curl -fsSL https://deb.nodesource.com/setup_lts.x \| sudo -E bash -` `sudo apt install nodejs`
PostgreSQL	`sudo apt install postgresql`

9. Troubleshooting

Issue	Command
Boot to recovery	GRUB → Advanced → Recovery Mode
Fix broken packages	`sudo dpkg --configure -a` `sudo apt install -f`
Reinstall GRUB (UEFI)	`sudo grub-install /dev/sdX` `sudo update-grub`
Clear journal logs	`sudo journalctl --vacuum-time=2weeks`
Boot errors	`journalctl -b -p err`
Regenerate initramfs	`sudo update-initramfs -u`
Check hardware	`lscpu`, `lsblk`, `lspci`, `lsusb`

10. Useful Tools to Install

sudo apt install \
    vim htop git curl wget unzip tree \
    net-tools ufw gnome-tweaks \
    build-essential dkms linux-headers-$(uname -r)

11. One-Liners

# Full system update + clean
sudo apt update && sudo apt full-upgrade -y && sudo apt autoremove && sudo apt clean

# Enable UFW with SSH allowed
sudo ufw allow OpenSSH && sudo ufw enable

# Show Ubuntu version
lsb_release -a

# Update snaps
sudo snap refresh

# Backup apt sources
cp /etc/apt/sources.list ~/sources.list.bak

# List all PPAs
grep ^deb /etc/apt/sources.list /etc/apt/sources.list.d/*

# Reboot into recovery
sudo systemctl reboot --firmware-setup  # (UEFI)

12. Ubuntu Flavors & Resources

Flavor	Command / Note
Ubuntu Server	Minimal CLI install
Ubuntu Desktop	Full GNOME experience
Kubuntu	KDE Plasma
Xubuntu	XFCE (lightweight)
Lubuntu	LXQt
Ubuntu MATE	Classic desktop

Official Docs: https://ubuntu.com/tutorials
Ask Ubuntu: https://askubuntu.com

13. Pro Tips

Use ubuntu-drivers autoinstall for NVIDIA/AMD drivers
Enable Minimized Updates in Software & Updates
Use apt-mark hold package to prevent updates
Backup with deja-dup (GUI) or rsync
Enable Firewall: sudo ufw enable

# Auto-accept reboots after updates (server)
sudo needrestart -a

November 8, 2025

Fedora Linux Cheatsheet

Essential commands for installation, package management, system administration, and troubleshooting
Uses dnf (primary) and flatpak/rpm-ostree (for Silverblue/Atomic). All privileged commands require sudo.

1. Installation (Live USB / Anaconda)

Task	Command / Action
Boot live ISO	Select “Start Fedora-Workstation”
Launch installer	Click “Install to Hard Drive”
Disk partitioning	Use Blivet-GUI or manual (`/boot/efi`, `/`, `swap`)
Post-install (first boot)	Complete user setup via GNOME Initial Setup
Manual install (netinstall)	Boot netinstall ISO → `dnf install @base-x` (or minimal)
Enable RPM Fusion (Free & Nonfree)	`sudo dnf install https://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-$(rpm -E %fedora).noarch.rpm` `sudo dnf install https://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-$(rpm -E %fedora).noarch.rpm`
Update system	`sudo dnf upgrade --refresh`

2. DNF (Package Management)

Action	Command
Update system	`sudo dnf upgrade --refresh`
Install package	`sudo dnf install package`
Remove package	`sudo dnf remove package`
Search package	`dnf search keyword`
List installed	`dnf list installed`
Autoremove unused	`sudo dnf autoremove`
Clean cache	`sudo dnf clean all`
View package info	`dnf info package`
List files in package	`rpm -ql package`
Which package owns file	`dnf provides /path/to/file`
Enable COPR repo	`sudo dnf copr enable user/repo`
History (undo/redo)	`dnf history` `sudo dnf history undo ID`

Flatpak (GUI & CLI)
flatpak install flathub org.mozilla.firefox
flatpak update
flatpak uninstall package

3. System Administration (systemd)

Task	Command
List services	`systemctl list-unit-files --type=service`
Enable service	`sudo systemctl enable service`
Start service	`sudo systemctl start service`
Status	`systemctl status service`
View logs	`journalctl -u service`
Reboot	`reboot`
Shutdown	`poweroff`
View kernel messages	`dmesg \| less`
Disk usage	`df -h`
Memory	`free -h`
Processes	`htop` or `top`
Kill process	`kill PID` or `pkill name`

4. Users & Permissions

Action	Command
Add user	`sudo useradd -m username`
Set password	`sudo passwd username`
Add to wheel (sudo)	`sudo usermod -aG wheel username`
Change owner	`sudo chown user:group file`
Change permissions	`chmod 755 file`

5. Networking

Task	Command
Check IP	`ip a` or `nmcli device show`
List Wi-Fi	`nmcli device wifi list`
Connect Wi-Fi	`nmcli device wifi connect SSID password "pass"`
Restart NetworkManager	`sudo systemctl restart NetworkManager`
Check DNS	`cat /etc/resolv.conf`
Firewall (firewalld)	`sudo firewall-cmd --list-all` `sudo firewall-cmd --add-service=http --permanent`

6. Filesystem & Storage

Task	Command
Mount USB	`sudo mount /dev/sdb1 /mnt/usb`
Unmount	`umount /mnt/usb`
Format ext4	`sudo mkfs.ext4 /dev/sdX1`
Check disk	`sudo fsck /dev/sdX1`
Find large files	`du -ah / \| sort -rh \| head -n 20`
Search files	`find / -name "filename" 2>/dev/null`

7. Fedora Variants

Fedora Silverblue / Kinoite (Immutable)

Task	Command
Rebase to new version	`rpm-ostree upgrade` `rpm-ostree rebase fedora:fedora/40/x86_64/silverblue`
Layer package	`rpm-ostree install package`
Remove layered	`rpm-ostree override remove package`
Rollback	`rpm-ostree rollback`
Check status	`rpm-ostree status`
Boot into previous	Select from GRUB

Toolbox (containerized dev)
toolbox create
toolbox enter

8. Troubleshooting

Issue	Command
Boot to recovery	GRUB → `e` → add `systemd.unit=rescue.target` → `Ctrl+X`
Fix broken deps	`sudo dnf distro-sync`
Reinstall all packages	`sudo dnf reinstall $(dnf list installed \| awk '{print $1}')`
Clear journal	`sudo journalctl --vacuum-time=2weeks`
Boot errors	`journalctl -b -p err`
Regenerate initramfs	`sudo dracut -f`
Update GRUB	`sudo grub2-mkconfig -o /boot/grub2/grub.cfg` (BIOS) `sudo grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg` (UEFI)

9. Useful Tools to Install

sudo dnf install vim htop git curl wget unzip tree dnf-automatic firewall-config

10. One-Liners

# Full update + clean
sudo dnf upgrade --refresh && sudo dnf autoremove && sudo dnf clean all

# Enable fastest mirrors
sudo dnf install dnf-plugins-core
sudo dnf config-manager --set-enabled fedora-cisco-openh264
echo "fastestmirror=True" | sudo tee -a /etc/dnf/dnf.conf

# Show orphan packages
dnf leaves

# Update Flatpaks
flatpak update

# Rebase Silverblue to latest
rpm-ostree update && reboot

11. Fedora Docs & Resources

Official Docs: https://docs.fedoraproject.org
Ask Fedora: https://ask.fedoraproject.org

# Install offline docs
sudo dnf install fedora-docs

12. Quick Install Scripts

# Post-install script (Workstation)
sudo dnf install https://rpmfusion.org/... (both repos)
sudo dnf upgrade --refresh
sudo dnf install vim htop git @development-tools

Pro Tip: Use gnome-software or dnfdragora for GUI package management.
For immutability: Silverblue + Toolbox + Flatpak = future-proof desktop

October 31, 2025

Arch Linux Cheatsheet

Essential commands for installation, package management, system administration, and troubleshooting
Assumes pacman as primary package manager. All commands require sudo unless run as root.

1. Installation (Live USB/ISO)

Task	Command
Update keyring (critical first step)	`pacman -Sy archlinux-keyring --noconfirm`
Sync mirrors (fastest)	`reflector --latest 10 --sort rate --save /etc/pacman.d/mirrorlist`
List disks	`lsblk -f` or `fdisk -l`
Partition disk (example: UEFI + root)	`cfdisk /dev/sdX`
Format partitions	`mkfs.fat -F32 /dev/sdX1` (EFI) `mkfs.ext4 /dev/sdX2` (root)
Mount partitions	`mount /dev/sdX2 /mnt` `mkdir -p /mnt/boot && mount /dev/sdX1 /mnt/boot`
Install base system	`pacstrap /mnt base linux linux-firmware`
Generate fstab	`genfstab -U /mnt >> /mnt/etc/fstab`
Chroot into system	`arch-chroot /mnt`
Set timezone	`ln -sf /usr/share/zoneinfo/Region/City /etc/localtime` `hwclock --systohc`
Set locale	Edit `/etc/locale.gen` → uncomment `en_US.UTF-8 UTF-8` `locale-gen` `echo "LANG=en_US.UTF-8" > /etc/locale.conf`
Set hostname	`echo "myhostname" > /etc/hostname`
Add to `/etc/hosts`	`127.0.0.1 localhost` `::1 localhost` `127.0.1.1 myhostname.localdomain myhostname`
Set root password	`passwd`
Install bootloader (GRUB UEFI)	`pacman -S grub efibootmgr` `grub-install --target=x86_64-efi --efi-directory=/boot --bootloader-id=GRUB` `grub-mkconfig -o /boot/grub/grub.cfg`
Enable network (systemd)	`pacman -S networkmanager` `systemctl enable NetworkManager`
Exit & reboot	`exit` `umount -R /mnt` `reboot`

2. Pacman (Package Management)

Action	Command
Update system	`pacman -Syu`
Install package	`pacman -S package`
Remove package (with deps)	`pacman -Rns package`
Search package	`pacman -Ss keyword`
List installed packages	`pacman -Q`
List explicitly installed	`pacman -Qe`
Clean cache (keep last 3 versions)	`paccache -rk 3`
Remove untracked packages	`pacman -Rns $(pacman -Qdtq)`
View package info	`pacman -Qi package`
List files in package	`pacman -Ql package`
Which package owns file	`pacman -Qo /path/to/file`
Sync database	`pacman -Syy`
Force refresh	`pacman -Syyu`

AUR Helper (yay/paru)
Install: pacman -S --needed git base-devel
git clone https://aur.archlinux.org/yay.git && cd yay && makepkg -si
Use: yay -S package (replaces pacman for AUR)

3. System Administration

Task	Command
List services	`systemctl list-unit-files --type=service`
Enable service	`systemctl enable service`
Start service	`systemctl start service`
Check status	`systemctl status service`
View logs	`journalctl -u service`
Reboot	`reboot`
Shutdown	`poweroff`
View kernel messages	`dmesg \| less`
Check disk usage	`df -h`
Check memory	`free -h`
List processes	`htop` or `top`
Kill process	`kill PID` or `pkill name`
Edit config (nano/vim)	`nano /path/to/file`
Backup pacman database	`cp -r /var/lib/pacman /backup/`

4. Users & Permissions

Action	Command
Add user	`useradd -m -G wheel username`
Set user password	`passwd username`
Enable sudo for wheel	`EDITOR=nano visudo` → uncomment `%wheel ALL=(ALL) ALL`
Change file owner	`chown user:group file`
Change permissions	`chmod 755 file`

5. Networking

Task	Command
Check IP	`ip a`
Test connection	`ping archlinux.org`
Wi-Fi (iwctl)	`iwctl` → `station wlan0 scan` → `connect SSID`
Enable Wi-Fi	`systemctl enable --now iwd`
Check DNS	`cat /etc/resolv.conf`
Restart NetworkManager	`systemctl restart NetworkManager`

6. Filesystem & Storage

Task	Command
Mount USB	`mount /dev/sdb1 /mnt/usb`
Unmount	`umount /mnt/usb`
Format ext4	`mkfs.ext4 /dev/sdX1`
Check filesystem	`fsck /dev/sdX1`
Find large files	`du -ah / \| sort -rh \| head -n 20`
Search files	`find / -name "filename"`

7. Troubleshooting

Issue	Command
Boot into recovery	Hold `Shift` at boot → GRUB → `e` → add `systemd.unit=rescue.target`
Fix broken packages	`pacman -Dk` (check deps) `pacman -Syu --overwrite '*'`
Reinstall all packages	`pacman -Qnq \| pacman -S -`
Clear journal logs	`journalctl --vacuum-time=2weeks`
Check boot errors	`journalctl -b -p err`
Regenerate initramfs	`mkinitcpio -P`
Update GRUB	`grub-mkconfig -o /boot/grub/grub.cfg`

8. Useful Tools to Install

pacman -S vim htop git curl wget unzip tree reflector rsync

9. One-Liners

# Full system update + clean
pacman -Syu && paccache -ruk0 && pacman -Rns $(pacman -Qdtq)

# Mirrorlist (fastest 10 servers)
reflector --latest 10 --sort rate --save /etc/pacman.d/mirrorlist && pacman -Syy

# Show orphan packages
pacman -Qdt

# Rebuild AUR packages after upgrade
yay -Syu --rebuildall

10. Arch Wiki Shortcut

Always check: https://wiki.archlinux.org

# Search wiki offline (install arch-wiki-docs)
pacman -S arch-wiki-docs
wiki-search "query"

Pro Tip: Keep archinstall script for automated installs:

pacman -S archinstall
archinstall

October 31, 2025