INPUT：
echo QUIT | openssl s_client -connect mail.google.com:443 | sed -ne '/BEGIN CERT/,/END CERT/p' OUTPUT：
depth=2 C = US, O = "VeriSign, Inc.", OU = Class 3 Public Primary Certification Authority verify return:1 depth=1 C = ZA, O = Thawte Consulting (Pty) Ltd., CN = Thawte SGC CA verify return:1 depth=0 C = US, ST = California, L = Mountain View, O = Google Inc, CN = mail.google.com verify return:1 DONE -----BEGIN CERTIFICATE----- MIIDIjCCAougAwIBAgIQHxn23jXdY6FCkYrVLMCrEjANBgkqhkiG9w0BAQUFADBM MQswCQYDVQQGEwJaQTElMCMGA1UEChMcVGhhd3RlIENvbnN1bHRpbmcgKFB0eSkg THRkLjEWMBQGA1UEAxMNVGhhd3RlIFNHQyBDQTAeFw0wOTEyMTgwMDAwMDBaFw0x MTEyMTgyMzU5NTlaMGkxCzAJBgNVBAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlh MRYwFAYDVQQHFA1Nb3VudGFpbiBWaWV3MRMwEQYDVQQKFApHb29nbGUgSW5jMRgw FgYDVQQDFA9tYWlsLmdvb2dsZS5jb20wgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJ AoGBANknyBHye+RFyUa2Y3WDsXd+F0GJgDjxRSegPNnoqABL2QfQut7t9CymrNwn E+wMwaaZF0LmjSfSgRSwS4L6ssXQuyBZYiijlrVh9nbBbUbS/brGDz3RyXeaWDP2 BnYyrVFfKV9u+BKLrebFCDmzQ0OpW5Ed1+PPUd91WY6NgKtTAgMBAAGjgecwgeQw DAYDVR0TAQH/BAIwADA2BgNVHR8ELzAtMCugKaAnhiVodHRwOi8vY3JsLnRoYXd0 ZS5jb20vVGhhd3RlU0dDQ0EuY3JsMCgGA1UdJQQhMB8GCCsGAQUFBwMBBggrBgEF BQcDAgYJYIZIAYb4QgQBMHIGCCsGAQUFBwEBBGYwZDAiBggrBgEFBQcwAYYWaHR0 cDovL29jc3AudGhhd3RlLmNvbTA+BggrBgEFBQcwAoYyaHR0cDovL3d3dy50aGF3 dGUuY29tL3JlcG9zaXRvcnkvVGhhd3RlX1NHQ19DQS5jcnQwDQYJKoZIhvcNAQEF BQADgYEAicju7fexy+yRP2drx57Tcqo+BElR1CiHNZ1nhPmS9QSZaudDA8jy25IP VWvjEgaq13Hro0Hg32ZNVK53qcXwjWtnCAReojvNwj6/x1Ciq5B6D7E6eiYDSfXJ 8/a2vR5IbgY89nq+wuHaA6vspH6vNR848xO3z1PQ7BrIjnYQ1A0= -----END CERTIFICATE-----
关于： https ： //superuser.com/questions/284150/how-to-add-self-signed-certificates-to-different-browsers – 这是关于“-i [文件名]”部分（如何获取文件生成）。
问：我怎样才能修改这个oneliner只输出公钥？
只要将2>&1添加到pipe道中的openssl命令中，使其将标准错误redirect到标准输出 – 您所看到的输出实际上正在转换为标准错误，所以sed不会像处理它那样处理它。 这工作：
$ echo QUIT | openssl s_client -connect mail.google.com:443 2>&1| sed -ne '/BEGIN CERT/,/END CERT/p' -----BEGIN CERTIFICATE----- MIIDIjCCAougAwIBAgIQHxn23jXdY6FCkYrVLMCrEjANBgkqhkiG9w0BAQUFADBM MQswCQYDVQQGEwJaQTElMCMGA1UEChMcVGhhd3RlIENvbnN1bHRpbmcgKFB0eSkg THRkLjEWMBQGA1UEAxMNVGhhd3RlIFNHQyBDQTAeFw0wOTEyMTgwMDAwMDBaFw0x MTEyMTgyMzU5NTlaMGkxCzAJBgNVBAYTAlVTMRMwEQYDVQQIEwpDYWxpZm9ybmlh MRYwFAYDVQQHFA1Nb3VudGFpbiBWaWV3MRMwEQYDVQQKFApHb29nbGUgSW5jMRgw FgYDVQQDFA9tYWlsLmdvb2dsZS5jb20wgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJ AoGBANknyBHye+RFyUa2Y3WDsXd+F0GJgDjxRSegPNnoqABL2QfQut7t9CymrNwn E+wMwaaZF0LmjSfSgRSwS4L6ssXQuyBZYiijlrVh9nbBbUbS/brGDz3RyXeaWDP2 BnYyrVFfKV9u+BKLrebFCDmzQ0OpW5Ed1+PPUd91WY6NgKtTAgMBAAGjgecwgeQw DAYDVR0TAQH/BAIwADA2BgNVHR8ELzAtMCugKaAnhiVodHRwOi8vY3JsLnRoYXd0 ZS5jb20vVGhhd3RlU0dDQ0EuY3JsMCgGA1UdJQQhMB8GCCsGAQUFBwMBBggrBgEF BQcDAgYJYIZIAYb4QgQBMHIGCCsGAQUFBwEBBGYwZDAiBggrBgEFBQcwAYYWaHR0 cDovL29jc3AudGhhd3RlLmNvbTA+BggrBgEFBQcwAoYyaHR0cDovL3d3dy50aGF3 dGUuY29tL3JlcG9zaXRvcnkvVGhhd3RlX1NHQ19DQS5jcnQwDQYJKoZIhvcNAQEF BQADgYEAicju7fexy+yRP2drx57Tcqo+BElR1CiHNZ1nhPmS9QSZaudDA8jy25IP VWvjEgaq13Hro0Hg32ZNVK53qcXwjWtnCAReojvNwj6/x1Ciq5B6D7E6eiYDSfXJ 8/a2vR5IbgY89nq+wuHaA6vspH6vNR848xO3z1PQ7BrIjnYQ1A0=
有很多方法可以做到这一点。 视情况而定，或者可能是更可取的。 我认为最直接的（如果不是最短的）方法就是这样的：
... | (while read l ; do [ "$l" != "DONE" ] || break ; done ; cat)