What is Curl: Command Line Tools Explained

When the Command Line Meets Proxy IP: Curl Tool's Magic Operation

A lot of newbies see the command line on the fear, but the old driver knows that Curl this tool is like a Swiss Army knife - look inconspicuous, the critical moment can save lives. Today we will nag how to use this black window artifacts to play around with proxy IP, especially with our ipipgo service to do a real-world demonstration.

A. What the hell is Curl?

Simply put, Curl is a tool that can send and receive data at the command line. It can use more than a dozen protocols to engage in data transfer, the most common is HTTP requests. For example, you want to see what data is returned to a site, do not need to open the browser, directly knock:

curl https://www.example.com

Once this command is executed, swish and spit out the web page source code for you. But it's not enough just to be able to use it that way, the focus is on the proxy play later.

Second, the proxy IP and Curl's perfect match combination

Friends who have used the proxy know that the direct request site is easy to expose the real IP. this time in the Curl to add a proxy parameter, like to the request to wear a cloak of invisibility:

curl -x http://123.45.67.89:8080 https://target-site.com

Here.-x parameterIt's just specifying a proxy server, but be careful with the format. When you use our ipipgo's proxy, you have to bring your account password for authentication:

curl -x http://user:pass@proxy.ipipgo.io:9021 https://目标网站

Three, must learn the five practical posture

1. Rapid detection of agent connectivity::
First, use this command to test whether the proxy is effective, the returned IP is the proxy IP is correct:

curl -x http://代理IP:端口 https://api.ipipgo.com/checkip

2. Timeout control to prevent jamming::
Add the -connect-timeout parameter to automatically abort after 10 seconds:

curl -x http://代理IP:端口 --connect-timeout 10 Destination URL

3. Disguise browser identity::
Add a User-Agent parameter to make the request look like a proper browser:

curl -x Proxy IP -A "Mozilla/5.0 (Windows NT 10.0; Win64; x64)..." Target URL

IV. Guide to Avoiding Potholes (Selected QA)

Q：Why does the proxy still return the real IP?
A: Ninety percent of the proxy format is written incorrectly, check whether it is missing the port number, or the account password is wrong. When you use ipipgo's proxy, please note that the service address should be the exclusive address given by the console.

Q: What should I do if the agent suddenly fails to connect?
A: First, use the ping command to test whether the proxy server is online, if there is no problem, try the ipipgo console one-key IP replacement function, three seconds to change a new export IP.

Fifth, the master of the advancement of the secret

Want to test proxy pool quality in bulk? Write a shell script to call Curl in a loop:

! /bin/bash
for ip in $(cat iplist.txt)
do
  curl -x $ip --connect-timeout 5 -o /dev/null -s -w "%{http_code}" https://api.ipipgo.com
done

This script will test the response status code of the proxy IP one by one, with the API interface provided by ipipgo, it can quickly filter out the available IPs.

Lastly, a tip: remember to add the -limit-rate parameter to control the speed when you use Curl to do the stress test, so as not to crash the server. If you need to switch IPs at high frequency, use ipipgo'sDynamic rotation of agentsIt's a great way to prevent blocking, as it automatically changes IPs for each request.