Beginner Linux Commands

Display Current User:

whoami

Get Current user UID - User ID, GID - Group Primary ID, Groups - Groups you belong too.

id

System Monitoring:
Install htop and run it.

sudo apt install htop
htop 

htop displays your systems performance. At the bottom of htop shows how you can use htop such as : search, filter, kill, etc. To exit htop just press q.

Show your current directory:

pwd

Show path to home directory:

~

List directories and files in your current directory:

ls

Create empty a file

touch file.txt

Create file with text in it:

echo "Hello World" > file.txt

Create a hidden file using the . :

echo "This file is hidden" > .cantsee

Display all files even hidden ones:

ls -a

Create a copy of file:

cp myfile.txt myfilecopy.txt

Copy to another directory:

cp myfile.txt newdirectory/

Moving files and changing name:

mv myfile.txt movedfile.txt

Move to new dirctory:

mv myfile.txt somedirectory/

Change name of directory:

mv somedirectory newnamedirectory

Move and rename one time:

mv somedir/myfile.txt ./somefile.txt

Remove a file:

rm file.txt

Remove empty directory:

rmdir somedir

Remove directory and all inside it:

rm -r somedir

Remove with prompts to confirm removal:

rm -i file.txt

Remove with recursive and force. Be careful with this command!

rm -rf somedir

Read file contents with cat

cat file.txt

Read file contents numbered

cat -n file.txt

Print the beginning of a file:

head # shows the first 10 lines
head -n1 file.txt  # -n1 prints the first line
head -c1 file.txt # -c1 prints the first character

print the last content of the file:

tail file.txt# shows last 10 lines
tail -n1 file.txt # -n1 prints the first line

See difference between 2 files:

diff myfile1 myfile2

diff -r ~/Downloads ~/Documents  # Directory diff with -r for recursive