Vi Editor basic user guide

vi is a screen-oriented text editor originally created for the Unix operating system.
Here are the few basic and necessary shortcuts to use vi editor effectively-

• '0'(zero) -move cursor to start of current line
• ':n' -move cursor to line n
• ':$' -move cursor to last line in file
• 'x' -delete single character under cursor
• 'dd' -delete entire current line
• 'dw' -delete the single word beginning with character under cursor
• 'yy' -copy (yank, cut) the current line into the buffer
• 'Nyy' -copy (yank, cut) the next N lines, including the current line, into the buffer
• 'p' -put (paste) the line(s) in the buffer into the text after the current line
• '/string' -search forward for occurrence of string in text
• '?string' -search backward 
• 'n'  -move to next occurrence of search string
• 'N'  -search for previous occurrence 
• 'u' -Undo last change
• 'ctrl + r'  - Redo 
• ':s/OLD/NEW/g'  -Replace OLD with NEW Globally (all) on current line
• ':%s/OLD/NEW/g'   -Replace OLD with NEW Every occurrence in file

Some Linux cli tips that you should know

In this post I'm giving few Linux CLI tips/shortcuts which i found very helpful and increase your speed while you are working on Linux using CLI. These tricks are very useful for those who are new to Linux.

1. 'CTL+L' - Clear screen. (you can use 'clear' also to clear the screen).
2. 'CTL+R' - Search recent commands from History.
3. 'CTL+A' - Take the cursor to the start of current command.
4. 'CTL+E' - Take the cursor to the end of currnet command.
5. 'CTL+W' - To erase one word in current command.
6. 'CTL+U' - To erase whole command.
7. 'CTL+Y' - To type the above command which was erased by 'CTL+U'.
8. 'CTL+D' - Exit or logout current session.
9. 'screen' - run multiple session inside a single session. 'CTL+A' then 'N' to go to next session and 'CTL+A' then 'P' to go to previous session.
10. 'CTL+C' - To halt current command
11. 'CTL+Z' - Stop current command
12. '!!' - Repeat previous command

Some Basic Networking Commands : Linux/Windows

I this post i am gonna write about some basic Networking commands used in Windows/Linux that i found important.

• Display Network configuration and interfaces
1. windows : "ipconfig" or "ipconfig /all"
2. Linux: "ifconfig" or "ifconfig interface-name"

• Show all running Tasks/Applications
1. windows : "tasklist" 
2. Linux: "ps aux" or "top" (Top is used to show memory and CPU used by running process)

• Kill a task
1. windows : "taskkill -pid 4000" or "taskkill -im iexplore.exe" ( Here -im is for image name)
2. Linux: "kill -9 pid"

• Displays the active TCP connections and ports on which the computer is listening
1. windows : "netstat -a"
2. Linux: "netstat -an"

• Diagnose the Domain Name System (DNS) : Resolves a hostname to IP address
1. windows : "nslookup google.com" 
2. Linux: "dig google.com"

• Ping : tool used to test whether a particular host is reachable or not.
1. windows/Linux IPv4 : "ping 74.125.236.73"
2. Windows/Linux IPv6: "ping6 9901::1"

• Path Ping : To see all the routers present in path to Destination
1. windows : "pathping google.com" 
2. Linux: "tracepath google.com"

• Assign IP/Subnet to Linux interfaces

1. Linux - IPv4 : "ifconfig eth0 192.168.1.2 netmask 255.255.255.0"
2. or Linux - IPv4 : "ifconfig eth0 2.2.2.2/24"
3. Linux - IPv6 : "ifconfig eth1 inet6 add 9901::2/64 "

• Delete IP from Linux interfaces
1. Linux - IPv4 : "ifconfig eth1 del 2.2.2.3 netmask 255.255.255.0"
2. Linux - IPv6 : "ifconfig eth1 inet6 del 9901::2/64"

• Change MTU(Maximum Transmit Unit through an Interface) of Linux interfaces
1. Linux : "ifconfig interface_name mtu value"
2. Linux : "ifconfig eth1 mtu 1300"

• Print routing tables
1. windows : "netstat -r" or "route print"
2. Linux- IPv4: "route -A inet" or "route -4" or "ip route"
3. Linux -IPv6: "route -A inet6" or "route -6" or "ip -6 route"

• Add/Delete static routes
1. windows- IPv4 : "route add 10.10.10.0 mask 255.255.255.0 192.168.1.12"
2. Windows - IPv6 : "netsh interface ipv6 add route 9901::/64 "Local Area Connection" 2001::1"
3. Linux-IP4: "route add -net 3.3.3.0 netmask 255.255.255.0 gw 1.1.1.1"
4. Linux-IP4: "ip route add 3.3.3.0/24 via 1.1.1.1"
5. Linux-IP6: "route -A inet6 add 9901::/64 gw 2001:0db8:0:f101::1"
6. Linux-IP6: "ip -6 route add 9901::/64 via 2001:0db8:0:f101::1"

• Trace route : to diagnostic tool for displaying the route
1. windows : "tracert google.com"
2. Linux: "traceroute google.com"

• Secure Shell :SSH is a network protocol for secure data communication and remote command execution

1. SSH-IPv4 : "ssh username@IPv4_address" Ex: ssh root@74.125.236.73 then it will ask you for password.
2. SSH-IPv6: "ssh username@IPv6_address"  Ex : ssh username@9901::1.

• Secure FTP : SFTP is a network protocol that provides file access, file transfer, and file management functionalities over any reliable data stream.
1. SFTP-IPv4 : "sftp username@IPv4_address". Ex: sftp root@74.125.236.73
2. Linux: "sftp username@[IPv6_address]". Ex:  sftp username@[9901::15]
• Secure Copy or SCP : Secure copy or SCP is a means of securely transferring computer files between a local host and a remote host or between two remote hosts. It is based on the Secure Shell (SSH) protocol.

1. SCP Linux : scp  username@IP:/Dir/File_name /local_dir
2. Ex:     scp  root@10.217.208.40:/root/roy.txt .
3. SCP windows : For windows you can use, WinSCP. Its a GUI based tool.