build all the binaries using a Makefile

Add a Makefile to build the local binaries. Rename all the commands
without a dash.

We can build the commands with `make all` or by being explicit, for
example `make bin/x509-info`.

Add a common package to keep track of build information (commit and
build date) so we can reuse the same pattern across all the commands.

1 files changed, 54 insertions, 0 deletions

diff --git a/cmd/x509info/README.md b/cmd/x509info/README.md
new file mode 100644
index 0000000..479771c
--- /dev/null
+++ b/cmd/x509info/README.md
@@ -0,0 +1,54 @@
+# 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 [DOMAIN]
+    x509-info (-f long) [DOMAIN]
+
+Options:
+    -f, --format      Format the result. Valid values: short, long. Default: short
+    -i, --insecure    Skip the TLS validation. Default: false
+    -p, --port        Specify the port. Default: 443
+    -v, --version     Print version information
+    -h, --help        Print this message
+```
+
+The default format will print a short message:
+``` shell
+$ ./bin/x509-info github.com
+github.com, valid until Thu, 14 Mar 2024 23:59:59 UTC (86 days left)
+```
+
+It's possible to get more details:
+``` shell
+$ ./bin/x509-info -f long github.com
+certificate
+  version: 3
+  serial: 17034156255497985825694118641198758684
+  subject: github.com
+  issuer: DigiCert TLS Hybrid ECC SHA384 2020 CA1
+
+validity:
+  not before: Tue, 14 Feb 2023 00:00:00 UTC
+  not after: Thu, 14 Mar 2024 23:59:59 UTC
+  validity days: 394
+  remaining days: 86
+
+SANs:
+  • github.com
+  • www.github.com
+```
+
+You can also check expired certificates:
+``` shell
+$ ./bin/x509-info -i expired.badssl.com
+*.badssl.com, not valid since Sun, 12 Apr 2015 23:59:59 UTC (expired 3172 days ago)
+```
+
+## Notes
+
+Could the same be achieved with a wrapper around `openssl` ? yes.