Bash scripting Notebook {part 2}

List of Contents:

1. File exploring and directory commands.
2. file manipulation commands
3. Networking(ifconfig,ping,ip,hostname,dig,traceroute,netstat)
4. text processing commands

File exploring and directory commands:

which — Display which program will be executed.

which bash
/usr/bin

type: Display information about command type.

less & more: less is a terminal pager program.

man: more is a command to view the contents of a text file one screen at a time.

cat: allows us to create single or multiple files, view contain of file, concatenate files and redirect output in terminal or files.

info: Info pages usually give more detailed information about a command then its respective man pages.

whatis: whatis searches a set of database files containing short descriptions of system commands for keywords and displays the result on the standard output. Only complete word matches are displayed.

mkdir : for creating directory .

rmdir: It is used for removing directory.

rm: It is used for removing files.

pwd: prints current working directory.

ls: ls is a command to list computer files.

strings: The strings command returns each string of printable characters in files.

file: determines the file type of a file.

cp: used for copy files or directoy.

cp [source] [destination]

mv: used for rename file or moving file.

mv [source] [destination]

Networking commands:

ifconfig-List the current network interface configuration

Displaying IP addresses

$ifconfig          #for list all the interface with ip address
$ifconfig wlan0      #for checking wlan0 interface ip address

changing the local IP address

$ifconfig wlan0 192.168.0.45    #it changes the local ip

Spoofing the hardware address (MAC address)

$ifconfig eth0 hw ether 08:00:27:27:80:4a

Name server and DNS (Domain Name Service)

Name servers assigned to the current system can be viewed by

$cat /etc/resolv.conf

dig-DNS lookup utility

DNS lookup commands

$nsloopup google.com
$host google.com

route -Showing routing table information

ping - check the connectivity of two hosts on a network

traceroute — displays the address of all intermediate gateways through which a packet travelled to reach a particular destination.

$traceroute google.com

netstat — netstat is another command for the network service analysis.

Use netstat -tnp to list opened port 

ssh -To connect to a remote host with the SSH server running.

ssh root@10.10.10.105        #root=username,10.10.10.105=hostname

netcat — Netcat is a computer networking utility for reading from and writing to network connections using TCP or UDP.

nc -lvpn 1111   #for listing on port 1111
nc 192.168.0.3 1111  #for connecting with sepecified ip and port

#On the receiver machine, run the following command:
nc -l 1234 > destination_filename
#On the sender machine, run the following command:
nc HOST 1234 < source_filename

curl- command line utility for transferring data from or to a server designed to work without user interaction.

wget — Wget is a computer program that retrieves content from web servers.

wget http://192.168.0.43:8080/a.py
#downloading file from local network

Iptable — administration tool for IPv4/IPv6 packet filtering and NAT

IP — IP is the transport layer protocol used by the Internet protocol family.

tcpdump: allows you to capture and analyze network traffic going through your system.

openvpn-connect with openvpn

$openvpn filename.ovpn

Text processing commands:

cut: for cutting in column fashion.

$ cat student_data.txt
No Name Mark Percent
1 Sarath 45 90
2 Alex 49 98
3 Anu 45 90
$ cut -f1 student_data.txt
No
1
2
3

awk: awk is a tool designed to work with data streams.

syntax:
awk ' BEGIN{ print "start" } pattern { commands } END{ print "end" }
file
$ seq 5 | awk 'BEGIN{ sum=0; print "Summation:" }
{ print $1"+"; sum+=$1 } END { print "=="; print sum }'
Summation:
1+
2+
3+
4+
5+
==
15

sed: steam editor is used for text replacement.

grep: for finding the pattern in the file