netstat when you cannot

netstat when you cannot

Author: rex_a

embNetstat.sh

@@ -0,0 +1,36 @@
+#!/bin/bash
+#
+# "embedded-device netstat"
+#
+# embNetstat.sh
+#	watered-down version of netstat for when
+#	netstat, lsof, etc are not available
+#
+# ./embNetstat.sh [tcp | udp]
+#
+# giving credit where credit is due, i adopted this from andreisid.  he has good milk:
+#	https://www.commandlinefu.com/commands/view/15313/check-open-ports-without-netstat-or-lsof
+#	https://www.commandlinefu.com/commands/by/andreisid
+#
+# **************
+# * escollapse *
+# * CISSP, PT+ *
+# *  20200204  *
+# **************
+#
+
+case "$1" in
+	"tcp")
+		echo "Open TCP Ports:"
+		declare -a array=($(tail -n +2 /proc/net/$1 | cut -d':' -f3 | cut -d' ' -f1))\
+			&& ((for port in ${array[@]}; do echo $((0x$port)); done) | sort -n)
+		;;
+	"udp")
+		echo "Open UDP Ports:"
+		declare -a array=($(tail -n +2 /proc/net/$1 | cut -d':' -f3 | cut -d' ' -f1))\
+			&& ((for port in ${array[@]}; do echo $((0x$port)); done) | sort -n)
+		;;
+	*)
+		echo "Usage: $0 [tcp | udp]"
+		;;
+esac