./ Week_01_LINUX
./Living my tale | Support desk agent by night, Student by day | Making magic happen ✨
I don’t like to talk much; let’s cut to the chase.” Sometimes brevity is the best policy, right?
Here's what I learned in week one. #Not so brief, point by point.
WHY LINUX
Free & Open source
Access to Source code
Multiple distributions available
Security and better malware protection
What is Kernel?
The kernel is a part of an OS that handles communication between hardware and software.
What is Shell?
Shell is a command line interpreter which translates commands entered by the user to a language understood by the kernel.
What is Shell script?
Shell scripts are the list of commands that are listed in order to execute.
Most basic Shells
C Shell
Ideal for learners comfortable with C language.
Network admins use
Korn Shell (KSH)
The interactive shell can be used for automation of many computer maintenance and system administration task.
Bourne-again Shell (Bash)
Easy to learn and most commonly used.
& let's categorize some essential Linux commands:
User & Groups
sudo useradd - creates a user
sudo passwd - provides a password to user
sudo userdel - deletes the user
sudo groupadd - creates a group
sudo groupdel - deletes a group
File Viewing and Editing
touch - creates a file
cat - displays the file content in terminal
cat -b : gives numbers to each non-blank line
cat -n : gives numbers to all the lines
cat -S : squeez the blank lines to one blank line
cat -e : provide dollar to the end of each line
cp - copies the file or directory
cp -n : do not overwrite an existing file
cp- u : updates the destination file
cp - r : copy directories recursively, even copies the hidden file
mv - moves the file or directory
mv -i : prompt before overwrite
mv -v : explain what is being done
rm - removes or deletes file or directory
- rm -r : remove directories and their contents recursively
mkdir - creates a directory
- mkdir -p : make parent directories as needed
rmdir - remove's directory
rmdir -p : removes bot parent and sub directories
rmdir -pv : removes as above with verbose
grep - works as ‘find’ in terminal
sort - sort content alphabetically
sort -r : returns in reverse order
sort -f : case insensetive
sort -n : sort in numerical order
Permissions
chown - to change the ownership of a file or directory
chmod - to change the permissions for file or directory.
lsof - list all the open files
- lsof - u user : all open files by a specific user
id - used to find out user name real user id u id group associated with the user and security context to the user
id -g : prints only effective group ids
id -G : prints all the group ids
id -n : prints name instead of numbers
id -r : prints real ids instead of numbers
tar - used to zip and unzip files of the .tar format
tar -cvf filename source foldername : Zip file
tar -xvf tarfile : Unzip file
cut - used extract and display selected content
- cut -c(column no.) file :
sed - text editor editing operation in non-interactive way (many manipulation possible)
- sed ‘s/baban /chagan /’ file name: replaces the word with a new word
uniq - filters out all the duplicate lines in a file.
history - shows the history of whole commands used
- history (last number of commands used): will show the last number of commands used.
Resources: Linux Tutorial For Beginners | Edureka | https://www.youtube.com/watch?v=Wgi-OfbP2Gw
Will learn the other commands in the following week (there are lots to learn🧐).
./See you next week…
