Basic Linux TutorialIntroduction – What is it? Why to learn? Linux installation directory structures Boot process Run levels in Linux Desktop Environments Different shells BASH Internal and External Commands Basic Linux Commands Important files and directories in Linux Environmental and Shell Variables Command history in Linux Character classes in Linux Text editors vim nano Searching files Creating new files Viewing File Contents File commands File permissions and ownership WildCards (Globbing) in files File compression Directory commands xargs command in Linux Comparing files Searching patterns using grep command Translating the characters using tr command Extracting data using cut command Stream editing using sed command Data extraction and reporting using awk command Sorting the file or string input uniq command in Linux Difference between grep, tr, cut, sed and awk commands Hardware commands Hard disk and memory space commands Working with Processes Managing Jobs Working with cron jobs Service command in Linux Network commands Managing Users and Groups Other Popular commands Standard streams and Redirection Pipes Package Managers in Linux
boot process in linux shellIn this section, we will see how the linux system boots. When we start the system, below sequence of events occur.
- Read BIOS and see the boot device(CD ROM, USB or hard disk).
- Try to locate the MBR (Master Boot Record) in boot device.
- MBR contains the GRUB which stores the details of the kernels available for booting.
- If there are multiple operating systems installed on your system, GRUB (also called as boot loader) displays the list of them and finally reads the selected kernel of the OS.
- Kernel executes init process and then starts various other services.
- Finally login prompt is displayed if the password is set for the user.
- /boot/grub/grub.conf – stores details about kernels
- /sbin/init – first process started in linux
- /etc/inittab – defines run levels of the system
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