Here I'm considering Ubuntu distro from Linux.
Show all local user of your machine
cut -d: -f1 /etc/passwd
Add new user
sudo adduser username
# or
sudo useradd username
Add new user without password
adduser --disabled-password --gecos "" username
User password change
sudo passwd username
Grant root access to an user
sudo usermod -aG sudo username
Log in to other user
su username
Log out
exit
4 => stands for "read"; shortly r
2 => stands for "write"; shortly w
1 => stands for "execute"; shortly x
0 => stands for "no permission."
u => user
g => group
o => Other (anyone else)
example
chmod 754 install_file.sh
here,
user will get read(4), write(2) and execute(1) permission; 4+2+1=7
group will get read(4) and execute(1) permission; 4+1=5
other will get only read(4) permission
check files permission
ls -l
Read only permission
chmod 4 filename
All permission (4+2+1=7)
chmod 7 filename
change ownership for directory and file to other user
sudo chown -R hnj directory
sudo chown -R hnj file.txt
Create a directory
mkdir DirectoryName
Rename directory
mv oldname newname
Move to the directory
cd DirectoryName
Move to hierarchical directory
cd DirectoryName/insideDirectoryName
Remove empty directory
rm -d DirectoryName
Remove non-empty directory
rm -r DirectoryName
Create new file
touch filename.txt # using touch
gedit filename.txt # using gedit
cat > filename.txt # using cat
Rename file
mv old.txt new.txt
Remove file
rm filename.txt
Remove multiple file
rm file1.txt file2.txt
File open with gedit editor
gedit file.txt
File open with nano terminal editor
nano file.txt
Check terminal command history
history
Save history in a text file
history > filename.txt
search in history with a specific text below will show all the command from history with java
history | grep java
Open firefox
firefox
Maven Spring boot project
mvn spring-boot:run
Create JAR of Maven Spring boot project
mvn package
Run JAR
java -jar filename.jar
Angular project
ng s --open
React project
yarn start
Rails project
rails s