Displays a text file’s contents a page at a time
Pager Utility
- Uses B-tree data structure to read and write data
- Made to handle large files
- Has its own integrated RAID functionality for:
- Scalability
- Performance
- Data integrity
btrfs (known as BUTTER FS)
/dev/disk/by-id
/dev/disk/by-label
/dev/disk/by-uuid
/dev/disk/by-path
Directories with device listings. Use the ls command to view contents.
3 utilities used to create and view disk partitions
fdisk
gdisk
parted
What are the (simplified) steps involved in booting a Linux system?
- Firmware conducts a power-on self test (POST)
- Firmware looks on bootable device for bootloader program
- Bootloader program loads Linux kernel program
- Linux kernel prepares some items
- Linux kernel kicks off system initialization
- System initialization starts services amongst other things
What are the classic steps in booting an older BIOS dependent machine?
•Firmware is basic input/output system (BIOS)
•Bootloader program is in the master boot record (MBR)
when booting from a hard drive
- MBR is on the first sector of boot drive, so it’s small
- Due to size, chainloading typically used
What are the most common bootloader programs for Linux machines?
- LILO
- GRUB Legacy
- GRUB2
SysVinit
Classic initialization system for Linux
Uses run levels (0-6)
What are the legacy GRUB configuration settings?
- default - Sets the default kernel (or OS) configuration to load
- timeout - Sets the amount of time prior to selected default kernel
- hiddenmenu - Keeps bootloader menu from displaying
•title - Designates OS configuration section;
provides verbiage for bootloader menu selection
•root - Sets disk/partition location of OS
•kernel - Provides virtual directory location of OS;
kernel options for loading OS
•initrd - Sets initial RAM disk or filesystem with needed driver
What are the steps in modern EUFI booting for a Linux machine?
•Firmware is unified extensible firmware interface (UEFI)
•UEFI uses a mini-bootloader (boot manager) to configure
bootloader program to use
- Bootloader program is in the extensible firmware interface (EFI) System Partition (ESP)
- ESP mounted on /boot/efi/ directory
- Check if system booted via UEFI: ls /sys/firmware/efi
Modern system initialization software that:
- Starts services in parallel
- Groups services (units) into targets
- Uses configuration files and systemctl for management
systemd
What are the 3 types of systemd statuses?
enabled - starts service at system boot
disabled - won’t start service at system boot
static - only starts service if manually started,
or if another service needs it at boot
