Here will be summary of me known commands

• sudo apt-get purge PROGRAM_NAME
• sudo apt-get autoremove --purge PROGRAM_NAME
• sudo apt-get autoclean

OpenSSL is a cryptography toolkit implementing the Secure Sockets Layer ( SSL v2/v3) and Transport Layer Security ( TLS v1) network protocols and related cryptography standards required by them.

Use cases

• Creation and management of private keys, public keys and parameters
• Public key cryptographic operations
• Creation of X.509 certificates, CSRs and CRLs
• Calculation of Message Digests
• Encryption and Decryption with Ciphers
• SSL/TLS Client and Server Tests
• Handling of S/MIME signed or encrypted mail
• Time Stamp requests, generation and verification

Generating a self-signed certificate pair

type is a command that describes how its arguments would be interpreted if used as command names.

type command_name

e.i. type nodejs

print distribution-specific information

lsb_release

e.i. lsb_release -a

print system information

uname

e.i. uname -s

copies files between hosts on a network

scp user@server1:/path/to/file user@server2:/where/to/put

for copy directory use scp -r user@server1:/path/to/folder user@server2:/where/to/put if you are on server and want to copy data to another server use this syntax: scp -r /path/to/folder user@server2:/where/to/put

Lists the status of all running background jobs.

jobs

with command fg number_of_process you move process form background to foreground and than you can kill it with ctrl + c

ssh -nNT -L host_post:remove_host_name:remove_port username@server_name

e.i. ssh -nNT -L 9000:localhost:5432 [email protected]

The man Command. The man command is used to format and display the man pages. The man pages are a user manual that is by default built into most Linux distributions (i.e., versions) and most other Unix-like operating systems during installation.

e.i. man ssh

free - Display amount of free and used memory in the system

free -h display in human format