runcon: add page (#3297)

pages/linux/runcon.md

@@ -0,0 +1,20 @@
+# runcon
+
+> Run a program in a different SELinux security context.
+> With neither context nor command, print the current security context.
+
+- Determine the current domain:
+
+`runcon`
+
+- Specify the domain to run a command in:
+
+`runcon -t {{domain}}_t {{command}}`
+
+- Specify the context role to run a command with:
+
+`runcon -r {{role}}_r {{command}}`
+
+- Specify the full context to run a command with:
+
+`runcon {{user}}_u:{{role}}_r:{{domain}}_t {{command}}`