In this tutorial we will learn about cURL and also find out different use cases where we can use this command line tool.
cURL is a command line tool for transferring data with URLs. It supports FTP, HTTP, HTTPS, proxy tunneling and many other protocols.
| Tool Name |
cURL |
| Developed By |
Daneil Stenberg |
| First release date |
March 20, 1998 |
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curl -sSL -D - https://www.google.com -o /dev/null
HTTP/2 200
date: Thu, 09 May 2019 14:47:17 GMT
expires: -1
cache-control: private, max-age=0
content-type: text/html; charset=ISO-8859-1
p3p: CP="This is not a P3P policy! See g.co/p3phelp for more info."
server: gws
x-xss-protection: 0
x-frame-options: SAMEORIGIN
set-cookie: 1P_JAR=2019-05-09-14; expires=Sat, 08-Jun-2019 14:47:17 GMT; path=/; domain=.google.com
set-cookie: NID=183=Kx7qT7AShnSFmdfmzp2HSJ1L_pXzVO8fNwUb7Ps7edudbRyrGivsIDpw688ut01484SfwrKfMVm74ryDmwXEhzqkeL89_uMh0W-XVFyAGW2wnC_GKxPZF-y69v-bvbDJKKJ_Qa6vs3Ll2KJiLCS_t6UE1okYMsVNE7jaT0PAD_s; expires=Fri, 08-Nov-2019 14:47:17 GMT; path=/; domain=.google.com; HttpOnly
alt-svc: quic=":443"; ma=2592000; v="46,44,43,39"
accept-ranges: none
vary: Accept-Encoding
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# specifying file name
curl -o setup.sh https://raw.githubusercontent.com/getredash/redash/master/setup/setup.sh
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 2941 100 2941 0 0 7419 0 --:--:-- --:--:-- --:--:-- 7408
# keeping the file name same
curl -O https://raw.githubusercontent.com/getredash/redash/master/setup/setup.sh
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 2941 100 2941 0 0 19477 0 --:--:-- --:--:-- --:--:-- 19606
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curl -H "Content-Type: application/json" www.google.com
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create file perf.txt
----
time_namelookup: %{time_namelookup}\n
time_connect: %{time_connect}\n
time_appconnect: %{time_appconnect}\n
time_pretransfer: %{time_pretransfer}\n
time_redirect: %{time_redirect}\n
time_starttransfer: %{time_starttransfer}\n
----------\n
time_total: %{time_total}\n
-----
curl -w "@perf.txt" -o /dev/null -s https://google.com/
time_namelookup: 0.014838
time_connect: 0.021859
time_appconnect: 0.136142
time_pretransfer: 0.136409
time_redirect: 0.000000
time_starttransfer: 0.239219
----------
time_total: 0.240644
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curl -I https://google.com 2>/dev/null | head -n 1 | cut -d$' ' -f2
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curl -I https://wordpress.com/ 2>/dev/null | head -n 1 | cut -d$' ' -f2
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curl -X POST https://api.mathpix.com/v3/latex \
-H 'app_id: trial' \
-H 'app_key: 34f1a4cea0eaca8540c95908b4dc84ab' \
-H 'Content-Type: application/json' \
--data '{ "src": "data:image/jpeg;base64,'$(base64 -i limit.jpg)'" }'
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No need to manually update /etc/hosts file. This option overrides DNS lookup on the fly.
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curl --resolve example.com:80:127.0.0.1 http://example.com
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