Simple Openssl recepie

The Openssl command has always been very opaque to me. Whenever I am doing cert operations I feel like I am a monk in the middle ages, copying scrolls I cannot read. Last night, I learned a simple command to inspect x509 certificate files that is short enough to commit to memory. I encourage everyone to use this command whenever they encounter .pem files and I encourage you to memorize it as well.

The command syntax is:

 openssl openssl x509 -in  -text

A full example:

nibz@host $ openssl x509 -in /etc/ssl/certs/Verisign_Class_1_Public_Primary_Certification_Authority.pem  -text
Certificate:
    Data:
        Version: 1 (0x0)
        Serial Number:
            3f:69:1e:81:9c:f0:9a:4a:f3:73:ff:b9:48:a2:e4:dd
    Signature Algorithm: sha1WithRSAEncryption
        Issuer: C=US, O=VeriSign, Inc., OU=Class 1 Public Primary Certification Authority
        Validity
            Not Before: Jan 29 00:00:00 1996 GMT
            Not After : Aug  2 23:59:59 2028 GMT
        Subject: C=US, O=VeriSign, Inc., OU=Class 1 Public Primary Certification Authority
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (1024 bit)
                Modulus:
                    00:e5:19:bf:6d:a3:56:61:2d:99:48:71:f6:67:de:
                    b9:8d:eb:b7:9e:86:80:0a:91:0e:fa:38:25:af:46:
                    88:82:e5:73:a8:a0:9b:24:5d:0d:1f:cc:65:6e:0c:
                    b0:d0:56:84:18:87:9a:06:9b:10:a1:73:df:b4:58:
                    39:6b:6e:c1:f6:15:d5:a8:a8:3f:aa:12:06:8d:31:
                    ac:7f:b0:34:d7:8f:34:67:88:09:cd:14:11:e2:4e:
                    45:56:69:1f:78:02:80:da:dc:47:91:29:bb:36:c9:
                    63:5c:c5:e0:d7:2d:87:7b:a1:b7:32:b0:7b:30:ba:
                    2a:2f:31:aa:ee:a3:67:da:db
                Exponent: 65537 (0x10001)
    Signature Algorithm: sha1WithRSAEncryption
         58:15:29:39:3c:77:a3:da:5c:25:03:7c:60:fa:ee:09:99:3c:
         27:10:70:c8:0c:09:e6:b3:87:cf:0a:e2:18:96:35:62:cc:bf:
         9b:27:79:89:5f:c9:c4:09:f4:ce:b5:1d:df:2a:bd:e5:db:86:
         9c:68:25:e5:30:7c:b6:89:15:fe:67:d1:ad:e1:50:ac:3c:7c:
         62:4b:8f:ba:84:d7:12:15:1b:1f:ca:5d:0f:c1:52:94:2a:11:
         99:da:7b:cf:0c:36:13:d5:35:dc:10:19:59:ea:94:c1:00:bf:
         75:8f:d9:fa:fd:76:04:db:62:bb:90:6a:03:d9:46:35:d9:f8:
         7c:5b
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----