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Bash: “$@” for Remaining Arguments

2024年7月8日
https://chatgpt.com/share/08f4fcbc-06fa-4bed-b884-5b971fb88030

Bash: $@ for Remaining Arguments

🧑 User

In bash what $ thing gives all remaining arguments?

🤖 Assistant

In Bash, the “$@” special parameter expands to all the positional parameters passed to a script or function, starting from the first one. This includes all the arguments that have not been assigned to any other variable, so “$@” effectively gives you all the remaining arguments.

Here’s an example to illustrate this:

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#!/bin/bash

# This script prints all the arguments passed to it.
echo "The script was called with $# arguments."
echo "The remaining arguments are: $@"

If you run this script with the command ./script.sh foo bar baz, it will output:

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The script was called with 3 arguments.
The remaining arguments are: foo bar baz

🧑 User

How do I use iperf?

🤖 Assistant

iperf is a command-line tool that allows you to measure network performance by sending and receiving data over a network. Here are the basic steps to use iperf:

Install iperf on your system: You can typically install iperf using your system’s package manager. For example, on Ubuntu, you can run sudo apt-get install iperf to install iperf.Choose a server: You need to choose a server to test the network performance against. The server should have iperf installed and be accessible over the network. You will need to know the IP address or hostname of the server.Start the server: On the server, run the command iperf -s to start the iperf server. This will listen for incoming connections from iperf clients.Run the client: On the client, run the command iperf -c to connect to the iperf server and start the network test. Replace with the IP address or hostname of the server.View the results: Once the test completes, iperf will display the results of the test, including the throughput, or the amount of data transferred per second.

Here’s an example of running iperf:

On the server:

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$ iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------

On the client:

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$ iperf -c 192.168.1.100
------------------------------------------------------------
Client connecting to 192.168.1.100, TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[  3] local 192.168.1.101 port 56916 connected with 192.168.1.100 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1.09 GBytes   937 Mbits/sec

In this example, iperf reports that the network throughput was 937 megabits per second (Mbps) for the duration of the test (10 seconds).