finger: add page (#2141)

pages/common/finger.md

@@ -0,0 +1,23 @@
+# finger
+
+> User information lookup program.
+
+- Display information about currently logged in users:
+
+`finger`
+
+- Display information about a specific user:
+
+`finger {{username}}`
+
+- Display the user's login name, real name, terminal name, and other information:
+
+`finger -s`
+
+- Produce multi-line output format displaying same information as `-s` as well as user's home directory, home phone number, login shell, mail status, etc.:
+
+`finger -l`
+
+- Prevent matching against user's names and only use login names:
+
+`finger -m`