Networking is a crucial aspect of system administration and scripting. Bash provides several tools and commands to interact with network services, transfer files, and manage network configurations. In this section, we will cover the following topics:

1. Basic Networking Commands
2. Transferring Files with scp and rsync
3. Using curl and wget for HTTP Requests
4. Network Diagnostics with ping, traceroute, and netstat

The ifconfig command is used to configure network interfaces. However, it is deprecated in favor of the ip command.

Example: Display Network Interfaces

or

Explanation:

• ifconfig: Displays all network interfaces and their configurations.
• ip addr show: Provides detailed information about network interfaces.

The ping command checks the connectivity between your machine and another host.

Example: Ping a Host

Explanation:

• ping google.com: Sends ICMP echo requests to google.com and waits for a response.

The traceroute command shows the path packets take to reach a network host.

Example: Trace Route to a Host

Explanation:

• traceroute google.com: Displays the route packets take to reach google.com.

The netstat command provides network statistics and information about network connections.

Example: Display Network Connections

Explanation:

• netstat -tuln: Lists all listening ports and their associated services.

The scp command securely copies files between hosts over SSH.

Example: Copy a File to a Remote Host

Explanation:

• scp localfile.txt user@remotehost:/path/to/destination: Copies localfile.txt to the specified path on the remote host.

The rsync command synchronizes files and directories between two locations.

Example: Synchronize a Directory

Explanation:

• rsync -avz /local/dir/ user@remotehost:/remote/dir/: Synchronizes the local directory with the remote directory, preserving file attributes and compressing data during transfer.

The curl command transfers data from or to a server using various protocols.

Example: Download a File

Explanation:

• curl -O http://example.com/file.txt: Downloads file.txt from the specified URL.

The wget command retrieves files from the web.

Example: Download a File

Explanation:

• wget http://example.com/file.txt: Downloads file.txt from the specified URL.

As previously mentioned, ping checks connectivity.

Example: Ping a Host

Explanation:

• ping -c 4 google.com: Sends 4 ICMP echo requests to google.com.

As previously mentioned, traceroute shows the path packets take.

Example: Trace Route to a Host

Explanation:

• traceroute google.com: Displays the route packets take to reach google.com.

As previously mentioned, netstat provides network statistics.

Example: Display Network Connections

Explanation:

• netstat -tuln: Lists all listening ports and their associated services.

1. Objective: Transfer a file to a remote host and verify connectivity.
2. Steps:
   • Use scp to copy a file to a remote host.
   • Use ping to check connectivity to the remote host.
   • Use traceroute to trace the route to the remote host.
   • Use netstat to check for active connections.

Solution:

In this section, we covered essential networking commands in Bash, including ifconfig, ip, ping, traceroute, and netstat. We also explored file transfer tools like scp and rsync, and HTTP request tools like curl and wget. These commands and tools are fundamental for network management and diagnostics in Bash scripting. In the next module, we will delve into automation and scheduling with cron jobs and other techniques.