ls - Lists the files and directories in the current directory.

pwd - Show present working directory.

cd - Changes the current directory. For example, cd ubuntu/ would change the current directory to cd ubuntu/.

mkdir - Creates a new directory. For example, mkdir DevOps would create a new directory named "DevOps".

rmdir - Deletes a directory. For example, rmdir DevOps would delete the directory "DevOps".

cp - Copies a file from one location to another. For example, cp file1.txt /home/ubuntu/dir1 would copy the file "file1.txt" to the directory /home/ubuntu/dir1/.

mv - Moves or renames a file. For example, mv file1.txt /home/ubuntu/dir1/newfile.txt would move the file "file1.txt" to the directory /home/ubuntu/dir1 and rename it to "newfile.txt".

cat - Displays the contents of a file. For example, cat file1.txt would display the contents of the file "file1.txt".