How to use the command trawl (with examples)

The trawl command is a tool that allows users to print out network interface information to the console, similar to other commands like ifconfig, ipconfig, ip, and ifdata. It provides a convenient and simple way to view and filter network interface information.

Use case 1: Show column names

Code:

trawl -n

Motivation: By using the -n flag, users can easily view the column names for the network interface information. This can be helpful for understanding the different fields present in the output.

Explanation: The -n flag is used to specify that the command should display column names in the output. It allows users to identify the different fields present in the network interface information.

Example output:

NAME       | MAC                | IP              | UP          | TX          | RX
-----------|--------------------|-----------------|-------------|-------------|-------------
eth0       | 00:11:22:33:44:55  | 192.168.1.100  | true        | 1.5 GB      | 2.3 GB
eth1       | AA:BB:CC:DD:EE:FF  | 10.0.0.1        | true        | 500 MB      | 300 MB
...

Use case 2: Filter interface names using a case-insensitive regular expression

Code:

trawl -f wi

Motivation: In many cases, users may want to filter the interface names based on specific criteria. By using the -f flag followed by a regular expression, users can easily filter and view only the interface names that match the given pattern.

Explanation: The -f flag is used to filter interface names based on a case-insensitive regular expression. In the example above, the regular expression wi is used to filter the interface names and display only those that contain the pattern wi (case-insensitive).

Example output:

NAME       | MAC                | IP              | UP          | TX          | RX
-----------|--------------------|-----------------|-------------|-------------|-------------
wlan0      | 00:11:22:33:44:55  | 192.168.1.100  | true        | 1.5 GB      | 2.3 GB
wlan1      | AA:BB:CC:DD:EE:FF  | 10.0.0.1        | true        | 500 MB      | 300 MB
...

Use case 3: Get a list of available interfaces

Code:

trawl -i

Motivation: Sometimes, users may need to retrieve a list of available network interfaces on their system. By using the -i flag, users can easily obtain a comprehensive list of all interfaces.

Explanation: The -i flag is used to request a list of all available network interfaces. When this flag is used, the command will display information about each interface, including its name, MAC address, IP address, status (UP or DOWN), amount of data transmitted (TX), and amount of data received (RX).

Example output:

NAME       | MAC                | IP              | UP          | TX          | RX
-----------|--------------------|-----------------|-------------|-------------|-------------
eth0       | 00:11:22:33:44:55  | 192.168.1.100  | true        | 1.5 GB      | 2.3 GB
wlan0      | AA:BB:CC:DD:EE:FF  | 10.0.0.1        | true        | 500 MB      | 300 MB
lo         | 00:00:00:00:00:00  | 127.0.0.1       | true        | 100 KB      | 100 KB
...

Use case 4: Include the loopback interface

Code:

trawl -l

Motivation: In some cases, users may want the loopback interface to be included in the network interface information. By using the -l flag, users can ensure that the loopback interface is displayed along with other interfaces.

Explanation: The -l flag is used to include the loopback interface in the output. The loopback interface is a virtual interface that allows communication within the same machine. By default, the loopback interface is not included in the output, but using the -l flag ensures that it will be displayed.

Example output:

NAME       | MAC                | IP              | UP          | TX          | RX
-----------|--------------------|-----------------|-------------|-------------|-------------
eth0       | 00:11:22:33:44:55  | 192.168.1.100  | true        | 1.5 GB      | 2.3 GB
wlan0      | AA:BB:CC:DD:EE:FF  | 10.0.0.1        | true        | 500 MB      | 300 MB
lo         | 00:00:00:00:00:00  | 127.0.0.1       | true        | 100 KB      | 100 KB
...

Conclusion:

The trawl command is a versatile tool that allows users to conveniently view network interface information. By using various flags, users can customize the output and filter the information based on specific criteria. Whether it is listing available interfaces, filtering by name, or including the loopback interface, the trawl command provides a simple and efficient solution for managing network interface information.