🚀 Day 2: Diving into Basic Linux Commands for the #90DaysOfDevOps Challenge! 🚀

Today, I took my first steps into the world of Linux, and I’m excited to share some essential commands that form the backbone of interacting with the Linux operating system. Here’s what I learned:

Basic Commands

1. pwd — print/present working directory
2. ls(list in series) — list a file &directory
3. ls -a to see hidden(.) files
4. ll(long list) ls — ltr shows in detail
5. date -current date ,time, year, seonds
6. date -s used for date set
7. cal used to view current month calender

cal -s Displays sunday as the first day of the week

cal -m Displays monday

cal -J Displays Julian dates

cal -y Displays a calender for the year

cal -3 to view 3 months calender (previous,current,next)

1. lsusb -usb related information
2. lspci — pheripheral connected device information
3. clear — to clear /clean the screen
4. history — to see the previous command history
5. tty — terminal command information
6. man — to get detailed information of a command it is well structured
7. free -storage is visible

free -h the storage is shown in human readable format

1. whoami — to see user
2. uname — name of the operating system i.e kernel information

uname -v to known the version of the kernel

uname -a all information about the kernel

1. passwd -to change the passwd
2. w — which user is logged in
3. dmidecode — complete information about system

dmidecode| less basically less is used to read the file

20.who — user & its time

21**.whatis** it provides one line information

22**.echo** — prints message on terminal & also used for file creation

23.rm — -help to known the rm related information

rm -rf r means recursive which first deletes the last file & then deletes last file and then delete one by one .

f means forcefully

v verbose → which shows the process of the recursive deletion

rm -rvf

ex : dir1/dir2/dir3/dir4/file1 → it will first delete the file1 →dir4 →dir3 →dir2 →dir1

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24.du — displays the folder size

1. df -hT — displays storage related information
2. info — in a descriptive way( very much in detail)
3. top — used to see current running process
4. diff filename — used to find out the difference between two files
5. tac filename — used to reverse the content of the file
6. Listing commands

ls option_flag arguments --> list the sub directories and files available in the present directory

Examples:

• ls -l-> list the files and directories in long list format with extra information
• ls -a -> list all including hidden files and directory
• ls *.sh --> list all the files having .sh extension.
• ls -i --> list the files and directories with index numbers inodes
• ls -d */ --> list only directories.(we can also specify a pattern)

Directoy commands

• pwd --> print work directory. Gives the present working directory.
• cd path_to_directory --> change directory to the provided path
• cd ~ or just cd --> change directory to the home directory
• cd - --> Go to the last working directory.
• cd .. --> change directory to one step back.
• cd ../.. --> Change directory to 2 levels back.
• mkdir directoryName --> to make a directory in a specific location

Directories (Filesystem hierarchy)

/root — it is the top level directory in linux hierarchy. All other directories are subdirectory of root.

/bin — it contains essential binary executable , basically used for basic system functionality. They are used to change the system booting and functionality.

/boot — this contains files needed for systems boot process such as kernel and boot loader.

/dev — it contains devices files & provides interface for interaction .

/etc — this contains configuration file that consist of various aspect of system, application and services .

/home — it contains local users home directory .

/lib — it contains 34 bit library files.

/lib64–64 bit shared library files.

/media — it is used as a mounting point for removable are such as usb devices.

/mnt — it is used as a temporary mounting point.

/opt — it is the most installed third party software.

/proc — this provides information about currently running software

/sbin — it contains system admin binary executable typically used by root user.

/temp — it is used for temporary used file ,which may be deleted at power off .

/usr — it contains user related files like libraries, binary file etc

/var — variable data file

/srv — service contains service related data

/run — temporary file system , holding data for process since last boot.

/sys — virtual file system which provides information about device , drives & kernel parameters.

Mastering these commands is fundamental for any aspiring DevOps engineer. I’m looking forward to applying these skills as I continue my journey!

Stay tuned for more updates!

#DevOps #Linux #SysAdmin #90DaysOfDevOps #LearnLinux #TechSkills #Automation #CloudComputing