plusk01 · April 22, 2019 14:59 · Apr 22, 2019
diff --git a/wifi_select.sh b/wifi_select.sh
@@ -0,0 +1,66 @@
+#!/bin/bash
+#
+# NetworkManager is trash for robots (periodic scanning causes
+# ~3s latency every 2 minutes). We have disabled Network Manager
+# (systemctl disable network-manager) and network interfaces are
+# now managed via /etc/network/interfaces, with authenticated
+# wireless managed by wpa_supplicant.
+#
+# Your /etc/network/interfaces probably looks like:
+#
+#	auto lo
+#	iface lo inet loopback
+#
+#	auto wlp1s0
+#	allow-hotplug wlp1s0
+#	iface wlp1s0 inet dhcp
+#		wpa_conf /etc/wpa_supplicant/wpa_supplicant.conf
+#		wireless-power off
+#
+# Use this script to switch between networks using wpa_supplicant
+# and then to force DHCP renewal.
+#
+# Parker Lusk
+# 19 April 2019
+
+# Find the available wireless networks that we can connect to
+SSIDs=$(cat /etc/wpa_supplicant/wpa_supplicant.conf | grep ssid | cut -d'"' -f 2)
+
+# What is the max network id that can be requested?
+NETID_MAX=$(echo -n "$SSIDs" | grep -c '^')
+NETID_MAX=$((NETID_MAX-1))
+
+function usage {
+  echo -e ""
+  echo -e "./wifi_select.sh NETID"
+  echo -e
+  echo -e "\tUse this tool to connect to a wireless network that has been configured"
+  echo -e "\tin /etc/wpa_supplicant/wpa_supplicant.conf. The \e[1mNETID\e[0m argument"
+  echo -e "\tmust be one of the following network IDs listed below:"
+  echo -e ""
+  # display each one with its connection number (wpa_cli list_networks)
+  count=0
+  for ssid in $SSIDs
+  do
+    echo -e "\t  \e[1m$count\e[0m\e[2m: $ssid\e[0m"
+    count=$((count+1))
+  done
+  echo -e ""
+  echo -e ""
+}
+
+# Make sure a valid network id has been supplied
+NETID=$1
+if [ -z "$NETID" ] || (( NETID > NETID_MAX )); then
+  usage
+  exit -1
+fi
+
+IFACE=wlp1s0
+
+wpa_cli -i $IFACE sel $NETID
+sudo dhclient $IFACE > /dev/null 2>&1
+
+echo -e ""
+echo -e "New IP assigned: $(ip a s $IFACE | sed -En -e 's/.*inet ([0-9.]+).*/\1/p')" 
+echo -e ""