## curl ## There might be scenarios where one needs to check the reachability of servers or the network connectivity, say for doing: - health checks. - troubleshooting. - sanity testing. - include them in a pipeline. - mimicking a request. - there can be N number of use cases.
This article is nothing about new technologies or tools, but it's just a refresher on the utility called curl and what all it can do. Curl really stands out and is a pretty popular utility :) This is an all-purpose tool that supports N number of protocols, and you can do a lot with it.
**Below are some of the usecases:** - Simple GET request: ``` $ curl https://google.com 301 Moved

301 Moved

The document has moved here. ``` - Get just the headers: ``` $ curl -I https://google.com HTTP/2 301 location: https://www.google.com/ content-type: text/html; charset=UTF-8 cross-origin-opener-policy-report-only: same-origin-allow-popups; report-to="gws" report-to: {"group":"gws","max_age":2592000,"endpoints":[{"url":"https://csp.withgoogle.com/csp/report-to/gws/other"}]} date: Wed, 30 Nov 2022 06:22:01 GMT expires: Fri, 30 Dec 2022 06:22:01 GMT cache-control: public, max-age=2592000 server: gws content-length: 220 x-xss-protection: 0 x-frame-options: SAMEORIGIN alt-svc: h3=":443"; ma=2592000,h3-29=":443"; ma=2592000,h3-Q050=":443"; ma=2592000,h3-Q046=":443"; ma=2592000,h3-Q043=":443"; ma=2592000,quic=":443"; ma=2592000; v="46,43" ``` - Get the HTTP status code and make your pipeline more meaningful based on the HTTP statusCode and their respective conditions. You can get N number of values out of it like http_code, http_version, content_type, etc. See its man page for more details `$ man curl`. - Instead of using awk/cut/grep/etc, this can come really handy. ``` $ curl -s -o /dev/null -w %{http_code} https://google.com 301 ``` - You can even use other HTTP methods like POST, DELETE, etc. with curl; we just need to specify --request or -X and the HTTP method name [the default method is GET]. ``` $ curl -X GET https://google.com 301 Moved

301 Moved

The document has moved here. ``` - If you want to follow the redirects -L can come handy. ``` $ curl -L google.com Google

networktroubleshooting

curl

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