# x509-info At this point it's pretty clear that I'll never remember the syntax for `openssl` to show various information about a certificate. At last I will not have to google for that syntax ever again. ## Usage ``` shell $ Usage: x509-info [OPTIONS] Arguments: Domain to check Options: -p, --port Port to check [default: 443] -i, --insecure Accept invalid certificate -f, --format [default: short] Possible values: - short: Format the output as one line of plain text - long: Format the output as plain text -h, --help Print help information (use `-h` for a summary) -V, --version Print version information ``` The default format will print a short message: ``` shell $ x509-info twitter.com twitter.com: Mon, 11 Dec 2023 15:59:59 -0800 (257 days left) ``` It's possible to get more details: ``` shell $ x509-info --format=long twitter.com certificate version: V3 serial: 0a:2c:01:b8:2b:5d:47:73:9a:5a:01:1a:6f:dc:1a:20 subject: C=US, ST=California, L=San Francisco, O=Twitter, Inc., CN=twitter.com issuer: C=US, O=DigiCert Inc, CN=DigiCert TLS RSA SHA256 2020 CA1 validity not before : Sat, 10 Dec 2022 16:00:00 -0800 not after : Mon, 11 Dec 2023 15:59:59 -0800 validity days : 365 remaining days: 257 SANs: DNS:twitter.com DNS:www.twitter.com ``` You can also check expired certificates: ``` shell $ x509-info --insecure expired.badssl.com : Sun, 12 Apr 2015 16:59:59 -0700 (it expired -2907 days ago) ``` ## Notes Could the same be achieved with a wrapper around `openssl` ? yes.