/unix-tools

UNIX tools and HOW-TOs

UNIX

UNIX commands and HOW-TOs

We'll mostly be using Debian distribution in our examples.

Hostname:

vi /etc/hostname (and put the name there like linode0)

New user:

adduser <username>
deluser <username>

#add to sudo
adduser <username> sudo

Change sudo timeout:

sudo visudo
Defaults env_reset,timestamp_timeout=-1    (it's in minutes, -1 means never expire)

Color prompt:

sudo apt-get install vim
sudo vi /etc/vim/vimrc
syntax on

Securing the server:

Follow this tutorial from Linode

Some helpful firewall rules.

    #Limiting port by IP address:
    -A INPUT -p tcp --dport 5000 -s <ip_address> -j ACCEPT
    -A INPUT -p tcp --dport 5000 -j DROP

    #Limiting SSH by IP
    -A INPUT -p tcp -s 128.112.0.0/16 -m state --state NEW --dport 22 -j ACCEPT

To refresh iptables rules:

    sudo iptables-restore < /etc/iptables.firewall.rules
    sudo iptables -L

Installing packages:

apt-cache search <package_name>