Living in the Shell #17; curl (HTTP/S Client) (Part 2)

curl 🌐

Makes requests in various protocols, including (but not limited to) HTTP/HTTPS/FTP/FTPS.

Add a custom header to request -H

curl https://postman-echo.com/get -H 'user-agent: curl' 

ℹ️ You can set any number of headers by repeating -H options.

Make a POST request with JSON body -d & -X

curl https://postman-echo.com/post \ -X POST \ -H 'content-type: application/json' \ -d '{"key":"value"}' 

{ "args": {}, "data": { "key": "value" }, "files": {}, "form": {}, "headers": { "x-forwarded-proto": "https", "x-forwarded-port": "443", "host": "postman-echo.com", "x-amzn-trace-id": "Root=1-61ba2f8f-304430e917ea20e7024a87c3", "content-length": "15", "user-agent": "curl/7.74.0", "accept": "*/*", "content-type": "application/json" }, "json": { "key": "value" }, "url": "https://postman-echo.com/post" } 

Read request body from file -d@

curl https://postman-echo.com/post \ -X POST \ -H 'content-type: application/json' \ -d @data-file.json 

Read request headers from file -H@

curl https://postman-echo.com/post \ -X POST \ -H @headers-file.txt \ -d @data-file.json 

⚠️ The headers file should be formatted as "key: value" per line.

Make a HEAD request -I

curl -I https://postman-echo.com/get 

ℹ️ Alternatively, you can use -X HEAD instead of -I.

See more detailed process logs -v

curl -v https://postman-echo.com/get 

This will print more low-level details, including protocol handshakes and negotiations.