iftop: add page (#3459)

pages/linux/iftop.md

@@ -0,0 +1,28 @@
+# iftop
+
+> Show bandwidth usage on an interface by host.
+> More information: <https://linux.die.net/man/8/iftop>.
+
+- Show the bandwidth usage:
+
+`sudo iftop`
+
+- Show the bandwidth usage of a given interface:
+
+`sudo iftop -i {{interface}}`
+
+- Show the bandwidth usage with port information:
+
+`sudo iftop -P`
+
+- Do not show bar graphs of traffic:
+
+`sudo iftop -b`
+
+- Do not look up hostnames:
+
+`sudo iftop -n`
+
+- Get help about interactive commands:
+
+`?`