dirb: add page (#6960)

pages/linux/dirb.md

@@ -0,0 +1,20 @@
+# dirb
+
+> Scan HTTP-based webservers for directories and files.
+> More information: <http://dirb.sourceforge.net>.
+
+- Scan a webserver using the default wordlist:
+
+`dirb {{https://example.org}}`
+
+- Scan a webserver using a custom wordlist:
+
+`dirb {{https://example.org}} {{path/to/wordlist.txt}}`
+
+- Scan a webserver non-recursively:
+
+`dirb {{https://example.org}} -r`
+
+- Scan a webserver using a specified user-agent and cookie for HTTP-requests:
+
+`dirb {{https://example.org}} -a {{user_agent_string}} -c {{cookie_string}}`