cURL Exercises for Testers

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Information about an endpoint

Try curl -I "https://www.workroom-productions.com/curl-exercises-for-testers/"

compare with curl -I "https://agiletestingdays.com/2025/session/the-art-of-crafting-your-custom-tools/"

Using with other tools

curl uses different output streams:

• stdout: HTTP response headers/body
• stderr: Progress information, error messages

When curl detects:

• Terminal output: Shows headers only, no progress meter
• Piped output: Shows progress meter to stderr, sends headers to stdout

See what happens when piping to other tools: curl -I "https://www.workroom-productions.com/curl-exercises-for-testers/" | grep "status"

Note the unexpected extra info compared with curl -I "https://www.workroom-productions.com/curl-exercises-for-testers/"

Manage this with -s

Compare with curl -sI "https://www.workroom-productions.com/curl-exercises-for-testers/" | grep "Status"

Information about a connection

try curl -vI "https://www.workroom-productions.com/curl-exercises-for-testers/"

Speed

try curl -w "Total time: %{time_total}s\n" -s -o /dev/null "https://www.workroom-productions.com/curl-exercises-for-testers/"

This uses the -w writeeout option, which exposes information about the transaction:

Variable	Description
%{content_type}	Content-Type of response
%{http_code}	HTTP status code
%{http_connect}	HTTP connect response code
%{local_ip}	Local IP address
%{local_port}	Local port number
%{num_connects}	Number of connections made
%{num_redirects}	Number of redirects
%{remote_ip}	Remote IP address
%{remote_port}	Remote port number
%{size_download}	Bytes downloaded
%{size_header}	Bytes of headers downloaded
%{size_request}	Bytes sent in request
%{size_upload}	Bytes uploaded
%{speed_download}	Download speed (bytes/sec)
%{speed_upload}	Upload speed (bytes/sec)
%{time_appconnect}	SSL/TLS handshake time
%{time_connect}	Connection establishment time
%{time_namelookup}	DNS lookup time
%{time_pretransfer}	Pre-transfer time
%{time_redirect}	Redirect time
%{time_starttransfer}	Time to first byte
%{time_total}	Total time
%{url_effective}	Final URL after redirects