How to: Use shortcut keys/Key combinations in Linux Terminal

1 Tab

When entering command, enter beginning of the command, file name or folder name or command option then press “Tab” key, it will complete the rest for you automatically or show all possible results.

2 Ctrl + C

Terminate/Kill the command or process, it will terminate the running process immediately. (signal SIGINT). It can be intercepted by a program, thus the program can clean itself up before exiting or not exit at all.

3 Ctrl + Z

Suspending a process by sending the SIGSTOP signal, it cannot be intercepted by the program.

4 Ctrl + D

Exit the current terminal. If you are using SSH, it will close it. If you are using a terminal directly, it will close the terminal window.

5 Ctrl + L

Clear terminal screen, same effect as “clear” command

6 Ctrl + A

Move the type cursor to the beginning of the line (Same as pressing “Home” key on keyboard)

7 Ctrl + E

Move the type cursor to the end of the line (Same as pressing “End” key on keyboard)

8 Ctrl + U

Wipe the line and move the type cursor to the beginning of the line (Instead of use “Backspace” key to clear the line slowly)

9 Ctrl + K

Wipe the content from the type cursor to the end of the line

10 Ctrl + W

Clear a word

Before Ctrl + W

Before Ctrl + W
Before Ctrl + W

After Ctrl + W

After Ctrl + W
After Ctrl + W

11 Ctrl + Y

It will paste text removed by Ctrl + U, Ctrl + U and Ctrl + K. If you have deleted text by mistake, this will be helpful.

12 Ctrl + P

Review last command, use repetitively to go back further. Many Terminal provides this review function by PageUp key as well. Some provide the review function by using up arrow key as well (↑).

13 Ctrl + N

Similar usage as Ctrl + P but opposite direction, this command navigate to more recent commands. Many Terminal provides this review function by PageDown key as well. Some provide the review function by using down arrow key as well (↓).

14 Ctrl + R

Used for search history commands

Bonus:

Alternatively, we can use “history” command to show all history command

To search from history command, we can use “history | grep searchTerm”


What’s the difference between CentOS Linux vs CentOS Stream

1 If you just want to test CentOS or use it as server: Download CentOS Linux

2 If you want to know what’s difference, read on

In short, CentOS Stream is in-between Fedora and RHEL, it provides clearner vision of what the next version of RHEL will be, give developer time to plan and create next-generation applications, so that they are compatible with future RHEL version. Whereas the CentOS Linux is the normal version we should use if we just want to setup another server.

Resources


Basics about Network configuration in Linux, IP commands, configuration files etc.

Table of Contents

1 Some useful basic IP commands

1.1 Use network/Interface configuration files to make permanent changes.

For CentOS/RHEL/Fedora etc.

File: /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE="eth0"
BOOTPROTO=static
ONBOOT=yes TYPE="Ethernet"
IPADDR=10.0.0.10
NAME="System eth0"
HWADDR=00:53:78:2C:7D:9E
GATEWAY=10.0.0.1

For Debian/Ubuntu/Kali Linux etc.

File: /etc/network/interfaces

auto eth0
iface eth0 inet static
address 10.0.0.10
netmask 255.255.255.0
gateway 10.0.0.1

Restart network services to make the changes take effect

sudo /etc/init.d/networking restart
 
OR
 
sudo service restart networking
 
OR
 
systemctl restart networking

1.2 Assign IP address to a specific interface (eth0 in this example) (nonpersistent, will be lost after system reboot)

sudo ip addr add 10.0.0.10 dev eth0

1.3 Remove IP address from a specific interface

sudo ip addr del 10.0.0.10/24 dev eth0

1.4 Check IP address

sudo ip addr
 
OR
 
sudo ip addr show
 
OR
 
sudo ifconfig

1.5 Enable Network interface

sudo ip link set eth0 up

1.6 Disable Network interface

sudo ip link set eth0 down

1.7 Check routing table

sudo ip route show

1.8 Add Static route

sudo ip route del 10.0.0.0/24

1.9 Add persistent static routes

For CentOS/RHEL/Fedora etc.

File: /etc/sysconfig/network-scripts/route-eth0

Add following

10.0.0.0/24 via 192.168.5.20 dev eth0

For Debian/Ubuntu/Kali Linux etc.

File: /etc/network/interfaces

Add following

up ip route add 10.0.0.0/24 via 192.168.5.20 dev eth0

Restart network services to make the changes take effect

sudo /etc/init.d/networking restart
 
OR
 
sudo service restart networking
 
OR
 
systemctl restart networking

1.10 Add default gateway

sudo ip route add default via 10.0.0.1

2 Network configuration file

For CentOS/RHEL/Fedora etc.

File: /etc/sysconfig/network-scripts/ifcfg-eth0

DEVICE=eth0
   #Alias name for the NIC
BOOTPROTO={static|dhcp|none|bootp}
   #Boot protocol, static|none;dhcp
IPADDR=192.168.10.10
   #Set IP address
NETMASK=255.255.255.0
   #Netmask
GATEWAY=192.168.10.1
   #Gateway
ONBOOT=yes|no
   #Activate the network port or not, on boot
HWADDR=00:1E:0B:8F:B0:D0
   #MAC address, if same as the default MAC address of the hardware, this line can be omitted 
DNS1=202.106.0.20
   #Specifiy DNS server
USERCTL=yes|no
   #Users (non-admin/root) allowed to enable/disable this port or not
PEERDNS=yes|no
   #Accept/Reject the DNS server from DHCP while BOOTPROTO is dhcp

For Debian/Ubuntu/Kali Linux etc.

File: /etc/network/interfaces

auto eth1
     #Automatically connect to Ethernet on boot
iface eth1 inet static
     #Assign IP address by static/dhcp
address 192.168.72.8
     #IP address
netmask 255.255.255.0
     #Netmask
gateway 192.168.72.1
     #Default gateway
dns-nameservers 8.8.8.8 4.4.2.2
     #DNS server

3 Hosts configuration

File: /etc/hosts

192.168.0.10 internalserver.mynet

4 Network Interface Controller (NIC) Naming

lo: Localhost loop

ppp#: Point-to-Point Protocol

eth: Ethernet

5 Network management tool

network tool and NetworkManager tool.

network

Restart network

sudo /etc/init.d/network restart

NetworkManager

It can be used to manager network easily, when X Window is not available this GUI tool can be used to manage network without the need to edit configuration file manually.

nmtui
nmtui
nmtui
NetworkManager TUI - nmtui
NetworkManager TUI – mntui

6 NetworkManager cli

NetworkManager provides cli tools as well alongside nmtui

nmcli con show
     #Get UUID table
nmcli dev
     #Check network device status
nmcli r wifi off
     #Turn off wifi
nmcli - commands
nmcli – commands

Start NetworkManager on boot

chkconfig NetworkManager on
 
OR
 
 systemctl enable NetworkManager

Start NetworkManager immediately

service NetworkManager start
 
OR
 
 systemctl start NetworkManager