Show negotiated TLS and certificate verification
Build a paste-ready command, then review its compatibility and effects before running it.
curl -sS -o /dev/null -w 'tls=%{ssl_version} verify=%{ssl_verify_result}\n' <url>Complete required fields to copy the generated command.
read-onlyno known side effects Compatibility
LinuxVerified for Linux using posix, bash, zsh syntax.
Operational knowledgereview due 2027-01-20
Requirementscurlcurl must be installed and available on PATH.
Version supportcurl Current supported releasesVerified for linux using posix, bash, zsh syntax; consult compatibility notes for platform-specific differences.
Expected signalstls=TLSv1.3 verify=0Representative successful output; values vary with the selected target and system state.
Known errorscurl: command not foundcurl is missing or is not available on PATH.
Verifycurl -sS -o /dev/null -w 'tls=%{ssl_version} verify=%{ssl_verify_result}\n' {{url}}The output matches the expected target and exits without an error.Rollback noteNot required: this command is read-only and does not change system state.
Command breakdown
01curlCommandRuns the curl stage of this one-liner.
02-sSOptionConfigures curl with the -sS option.
03-oOptionSelects an output file or output format for this command.
04/dev/nullArgumentPasses /dev/null to curl.
05-wOptionConfigures curl with the -w option.
06'tls=%{ssl_version} verify=%{ssl_verify_result}\n'ArgumentPasses 'tls=%{ssl_version} verify=%{ssl_verify_result}\n' to curl.
07<url>ParameterA value supplied in the Fill parameters section.
Example input
curl -sS -o /dev/null -w 'tls=%{ssl_version} verify=%{ssl_verify_result}\n' https://example.com
Example output
tls=TLSv1.3 verify=0
Illustrative output — exact values vary by system and data.
Official sources