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More Linux CLI Videos - • HowTo Linux Cli #HowToLinuxCLI #Linux #CommandLine #CLI #Terminal #Bash #Shell
0 - HowTos Linux Boot Process ✅ How to Check if Your Computer Uses BIOS or UEFI Why: Knowing this helps you understand how your computer boots and what files are needed.
Steps:
Open a terminal (press Ctrl+Alt+T) Run: ls -la /sys/firmware/efi/ If you see output, you have UEFI. If not, you likely have BIOS.
Alternative:
sudo dmesg | grep -i efi 📂 How to Find Your Boot Partition (UEFI Only) Why: This is where the boot files live in modern computers.
Steps:
Look for the /boot/efi folder: ls -la /boot/efi/ If it exists, that's your EFI System Partition. 📝 How to See What Operating Systems Are Installed Why: To see all your boot options and understand what's on your computer.
Steps:
At startup, when GRUB menu appears: Don't press anything yet You'll see a list like "Ubuntu", "Windows", etc. If you want to see it in terminal: cat /boot/grub/grub.cfg | grep -i menuentry 🛠️ How to Change Default Boot Option Why: To make your preferred OS boot automatically.
Steps:
Edit GRUB settings: sudo nano /etc/default/grub Find line GRUB_DEFAULT= and change the number or name (e.g., GRUB_DEFAULT="Ubuntu"). Update GRUB: sudo update-grub 📦 How to Check What Kernel Version You're Running Why: Shows which Linux version you have installed.
Steps:
In terminal: uname -r Example output might be: 5.4.0-72-generic
🔧 How to See What Files Are in Your Initramfs Why: To understand what drivers and tools are loaded early in the boot.
Steps:
List contents: sudo lsinitrd | head -20 Or view full content: sudo lsinitrd | less 🔍 How to See What Services Are Starting at Boot Why: Understand what programs run when your system starts.
Steps:
Check services that start at boot: systemctl list-unit-files --state=enabled | head -20 📋 How to Find Your Root Filesystem Location Why: This tells where the main Linux folder lives on your hard drive.
Steps:
Check fstab file: cat /etc/fstab Look for lines with /dev/sda1 or similar device names.
❗ How to Boot from a Different Kernel if Current One Fails Why: If your current kernel breaks, you can try an older one.
Steps:
At GRUB menu, press e (edit) Find the line starting with linux and add recovery at the end: linux ... recovery Press Ctrl+X to boot 🔄 How to Fix Bootloader Issues Why: If you can't boot into your OS anymore.
Steps:
Boot from a live USB Mount your root partition: sudo mount /dev/sda1 /mnt Reinstall GRUB: sudo grub-install --root-directory=/mnt /dev/sda 📁 Boot - Key Files to Remember File/Directory Purpose /boot/grub/grub.cfg Where GRUB finds all OS options /boot/vmlinuz The Linux kernel image /boot/initrd.img or /boot/initramfs.img Temporary root filesystem /etc/fstab Tells where the real hard drive folders are /boot/efi EFI partition needed for UEFI systems 🧪 How to Make a Boot Menu Change Open terminal Edit GRUB config: sudo nano /etc/default/grub Change GRUB_TIMEOUT=5 to GRUB_TIMEOUT=10 Save and exit (Ctrl+O, then Ctrl+X) Update GRUB: sudo update-grub Now when you restart, the boot menu will wait 10 seconds instead of 5