Exploring the Fundamentals: A Comprehensive Guide to Linux for Beginner

#devops #linux #cicd #opensource

Linux:

Linux is kernel not OS
Linux is not a UNIX derivative. It was written from scratch
A Linux distribution is the Linux kernel and a collection of software that together creates an OS.

Linux Features:

Open source
Secure
Simplified updates for all installed software
Light weight
Multi-User or Multi-Task
Multiple distributions – RedHat, Debian, Fedora etc.

File System Hierarchy:
/home - home directory for other user /root – It is home directory for root user /boot – It contains bootable files for Linux /etc - It contains all configurations files. /usr – By default software are installed in this directory /bin – It contains commands used by all users /sbin - It contains commands used by only root user /opt – Optional application software Packages /dev – Essentials device files. This includes terminal devices, usb or any devices attached to the system.

Linux Commands & It’s use cases:

cat command
– The cat command is one of the most universal tools, yet all it does is Copy standard input to Standard Output.
Touch Command -

Vi editor -

A programmer text editor
It can be used to edit all kinds of plain text, it is specially useful for editing programs, mainly used for Unix programs.

Notes: :w – to save :wq or :x – To save and quit :q – quit :q! – force quit, no save
Vi is a standard whereas ‘nano’ has to be available depending on the linux we use.

rmdir – This command is used to remove the specified directory (empty) rmdir -p – Removes both the parent and child directory rmdir -pv – Removes all the parent and sub-directories along with verbose. rm -rf – Removes even non-empty file and directory. Rm -rp – Removes non-empty directories including parent and sub directory. rm -r – Removes empty directory hostname Ifconfig, cat /etc/os-release yum install httpd yum remove httpd yum update httpd service httpd start service httpd status chkconfig httpd on chkconfig httpd off which whoami echo yum list intalled useradd- To create user groupadd – To create a group gpasswd -a/-m – To add user into group, to add multiple user ln – Hardlink/ backup ln -s – Softlink/ short cut tar – Tar is an archiver used to combine multiple files into one gzip – It is a compression tool used to reduce the size of a file wget – It is the non-intracity network downloader.