File and Directory Management

Manage files and directories efficiently using these commands:

List Directory Contents: ls

Detailed listing

ls -l

Include hidden files.

ls -a

Change Directory: cd

Navigate to a specific directory.


cd /path/to/directory 

Print Working Directory: pwd

Shows the current directory.

pwd

Copy Files or Directories: cp

Copy file1 to file2

cp file1 file2

Copy directories recursively.

cp -r dir1 dir2

Move or Rename Files:

Move file1

mv file1 /path/to/destination

Rename a file or directory


mv oldname newname

Remove Files or Directories:

Remove a file

rm file

Remove a directory and its contents recursively.


rm -r dir

Create a New Directory:

mkdir newdir

Remove an Empty Directory:

rmdir emptydir

Remove a Directory with its Content:

rmdir  -r dir

File Permissions and Ownership

Control access to files and directories with these commands:

Change File Permissions:

Set permissions (read/write/execute for owner, read/execute for group and others)


chmod 755 file

Change File Owner and Group:

chown user:group file

Make current user to own a file/directory

chown $USER:$USER file/direcctory

Zipping and Unzipping Files

Manage compressed files with the following commands:

Zip a File or Directory:

zip -r archive_name.zip /path/to/directory_or_file

Unzip a File:

unzip archive_name.zip

Package Management

Manage software packages with these commands: (apt- for Ubuntu or Debian, yum for Red Hat and dnf for Fedora, in this example I have used Ubuntu)

Update Package List:

sudo apt update

Upgrade Installed Packages:

sudo apt upgrade

Install a New Package:

sudo apt install package_name

Remove a Package:

sudo apt remove package_name

Remove Unnecessary Packages:

sudo apt autoremove

System Monitoring and Management

Monitor and manage system resources using these commands:

Display Real-Time System Processes:

top

Interactive Process Viewer:

htop #(requires installation)

Display Disk Space Usage:

df -h #for a human-readable format.

Display Disk Usage of Files and Directories:

du -sh /path/to/dir #for a human-readable summary.

Display Memory Usage:

free -h #for a human-readable format.

Report a Snapshot of Current Processes:

ps aux

Terminate Processes:

Terminate a process by its Process ID.

kill PID

Terminate all processes with the specified name.

killall process_name 

Restart the System:

reboot

Shut Down or Restart the System:

Shut down immediately.


shutdown now

Shutdown immediately.

shutdown -r now

Network Management

Configure and manage network settings with these commands:

Show IP Addresses and Network Interfaces:

ip addr

Check Connectivity to Another Host:

ping hostname_or_ip

Investigate Sockets:

Display TCP/UDP listening ports.

ss -tuln

User and Group Management

Create and manage users and groups with the following commands:

Create a Normal User:

sudo adduser newusername

Create a Sudo User:

sudo adduser newusername

sudo usermod -aG sudo newusername

System Information

Retrieve system details with these commands:

Print System Information:

uname -a

Show Ubuntu Version Information:

lsb_release -a

Basic Working with the Nano Editor

Edit text files with Nano, a simple command-line text editor:

Open a File:

nano filename

Save and Exit: Press Ctrl + O to save, then Ctrl + X to exit.

Exit Without Saving: Press Ctrl + X, then N to discard changes.

Basic Working with the Vi Editor

Edit text files with Vi (or Vim), a powerful text editor:

Open a File:

vi filename

Switch to Insert Mode: Press i to start editing.

Save and Exit: Press Esc, type :wq, and press Enter.

Exit Without Saving: Press Esc, type :q!, and press Enter.

Installing and Using curl

Transfer data with curl, a versatile command-line tool:

Install curl:

sudo apt update
sudo apt install curl

Fetch a URL:

curl http://example.com

Download a File:

curl -O http://example.com/file

Using wget

Download files from the web with wget:

Install wget:

sudo apt update
sudo apt install wget

Download a File:

wget http://example.com/file

Download a File with a Different Name:

wget -O newfilename http://example.com/file

SSH Connection to a Server

Securely access remote servers using SSH:

Using a Password:

ssh username@hostname_or_ip

Using an SSH Key File:

ssh -i /path/to/keyfile username@hostname_or_ip

Uploading and Downloading Files via SSH

Transfer files securely between your local system and a remote server:

Upload a File:

scp /local/path/to/file username@hostname_or_ip:/remote/path

Download a File:

scp username@hostname_or_ip:/remote/path/to/file /local/path

These are a few linux commands, if you get sudo prtmission error for a command, then just add sudo befor the command.