mkdir dir	create single directory dir
mkdir dir1 dir2	create multiple directories dir1 dir2
mkdir -p dir/a/b/c	create nested directory dir/a/b/c
mkdir dir{1..10}	created 10 numbered directories from dir1 to dir10
rm -r dir	remove dir recursively
touch file	create empty file file
touch file1 file2	create multiple files file1 file2
touch file{1..10}	create 10 numbered files from file1 to file10
cp -rf /dir/file1 /dir2	copy file file1 to dir2 directory recursively and forcefully
mv /dir/file1 /dir2	move file file1 to dir2 directory
rm file1	remove file file1
ls -al	show files - both regular & hidden files and their permissions
cat file1	display contents of file1
find /dir1 -name file1	find file1 under /dir1 directory
find /dir1 -perm 664	find all files/directories with read, write permission to owner and group, read permission for others in directory dir1
find /dir1 -empty -exec rm -r {}**	find and remove all empty files/directories from /dir1
wc -l file1	count the number of lines in file1
wc -w file1	count the number of words in "file1*
head file1	display top 10 lines of file1
head -n 20 file1	display top 20 lines of file1
tail file1	display last 10 lines of file1
tail -n 20 file1	display last 20 lines of file1

pwd	show present working directory
uname	show name of the kernel
uname -r	show kernel version
cd	change directory
clear	clear the screen
whoami	show current login user name
history	show list of previously used commands
date	show time and date
echo "Hello"	display Hello text
sudo	run commands as super user

Basic info