cURL

Introduction

CURL is a Command Line Tool to transfer data from or to a server using the support of various protocols. The various protocols used are:

DICT, FILE, FTP, FTPS, GOPHER, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, POP3, POP3S, RTMP, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET and TFTP.

By default, the result is displayed on the terminal but we can even save the data inside a file. We can even download images from servers. There are various other features which will be explained further.

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Features

• Supports many protocols
• SSL Support and many authentication methods
• For downloads, you can even mention range
• Multiple URL support (All in the same connection)
• Library of its own LIBCURL (Stable API)- So that can be used with multiple and scripting languages to do web scraping better
• Even large files more than 2GB can be downloaded

Probably the reasons to be used

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Demo

We will be using a website which provides fake online REST API for demo purpose.

To display data

curl https://jsonplaceholder.typcode.com/posts

Example with id = 3

To create a file having the data

curl -o data.txt curl https://jsonplaceholder.typcode.com/posts
cat data.txt

Downloading Images and Files

curl -O https://ichef-1.bbci.co.uk/news/660/cpsprodpb/E9DF/production/_96317895_gettyimages-164067218.jpg

Even Limit file download size

curl -O --limit-rate 1M https://ichef-1.bbci.co.uk/news/660/cpsprodpb/E9DF/production/_96317895_gettyimages-164067218.jpg

Few HTTP requests - Do a POST request

curl --data "title=Hello&body=Hello World" https://jsonplaceholder.typcode.com/posts

Do a PUT request

curl -X PUT -d "title=OlleH" https://jsonplaceholder.typcode.com/posts/101

Do a DELETE request

curl -X DELETE https://jsonplaceholder.typcode.com/posts/101

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