This script will reconnect your TP-Link TL-WDR3600 router. The script works with the latest firmware

tplink-reconnect.sh

#!/bin/bash

# The MIT License (MIT)
# 
# Copyright (c) 2015
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

#
# Propose of the script:
#
# This script will reconnect your TP-Link Router. if node.js is installed the
# new ip will be printed to stdout
# tested with:
#       * TL-WDR3600 (fw: 3.14.1 Build 141022 Rel.33470n)
# (it may work with other TP-Link router with similar firmware)
#
# WARNING: Even if you login with correct username and password the router may lock
# the loggin if your run the script ten times in a short period.
#
# Dependency: bash, md5sum, awk, base64, perl, curl
# Optional dependency: node.js
#
# Windows user may take a look at MinGW or Cygwin
#
# usage: ./tplink-reconnect.sh [<user> [<password> [<ip>]]]
# or just modify the values directly in this file.
# If you did not modifed the login you can run the script without any argument
# 


IP=${3:-"tplinkwifi.net"}
USER=${1:-"admin"}
PASSWORD=${2:-"admin"}

PASSWORD=`echo -n "${PASSWORD}" | md5sum | awk '{ print $1 }'`
auth=`echo -n "${USER}:${PASSWORD}" | base64`
AUTH="Basic $auth"
ENC_AUTH_COOKIE="Authorization="`perl -MURI::Escape -e 'print uri_escape($ARGV[0]);' "${AUTH}"`

RESPOND=`curl -ss "${IP}/userRpm/LoginRpm.htm?Save=Save" --cookie "${ENC_AUTH_COOKIE}"`

re="http\://[0-9A-Za-z.]+/([A-Z]+)/userRpm/Index.htm"
if [[ $RESPOND =~ $re ]]
then
    echo 'Login succesfully'
    KEY=${BASH_REMATCH[1]}
    
    DISCONNECTURL="$IP/$KEY/userRpm/StatusRpm.htm?Disconnect=Disconnect&wan=1"
    CONNECTURL="$IP/$KEY/userRpm/StatusRpm.htm?Connect=Connect&wan=1"
    
    echo "disconnecting WAN ..."
    curl -ss "$DISCONNECTURL" --cookie "${ENC_AUTH_COOKIE}" --referer "http://$IP/$KEY/userRpm/StatusRpm.htm" > /dev/null
    
    echo "connecting WAN ..."
    RESPOND=`curl -ss "$CONNECTURL" --cookie "${ENC_AUTH_COOKIE}" --referer "http://$IP/$KEY/userRpm/StatusRpm.htm"`
    
    if [ `which node 2> /dev/null` ]
    then
        echo -n "Waiting for new ip "
        WANIP="0.0.0.0"
        while [ $WANIP == "0.0.0.0" ]
        do
            RESPOND=`curl -ss "$IP/$KEY/userRpm/StatusRpm.htm" --cookie "${ENC_AUTH_COOKIE}" --referer "http://$IP/$KEY/userRpm/StatusRpm.htm"`
            re="(var\swanPara.+)</SCRIPT>\s<META"
            if [[ $RESPOND =~ $re ]]
            then
                info=${BASH_REMATCH[1]}
                WANIP=`node -e "$info console.log(wanPara[2]);"`
            fi
            echo -n "."
            sleep 1
        done
        
        echo ""
        echo "Your IP: $WANIP"
    fi
    exit 0
else
    echo 'Login failed!'
    echo 'You could have executed the script too often in a short period! In this case try again in 2h.'
fi

exit -1

I edit the script to restart it:

IP=${3:-"192.168.1.1"}
USER=${1:-"user"}
PASSWORD=${2:-"password"}

PASSWORD=`echo -n "${PASSWORD}" | md5sum | awk '{ print $1 }'`
auth=`echo -n "${USER}:${PASSWORD}" | base64`
AUTH="Basic $auth"
ENC_AUTH_COOKIE="Authorization="`perl -MURI::Escape -e 'print uri_escape($ARGV[0]);' "${AUTH}"`

RESPOND=`curl -ss "${IP}/userRpm/LoginRpm.htm?Save=Save" --cookie "${ENC_AUTH_COOKIE}"`

re="http\://[0-9A-Za-z.]+/([A-Z]+)/userRpm/Index.htm"
if [[ $RESPOND =~ $re ]]
then
    echo 'Login succesfully'
    KEY=${BASH_REMATCH[1]}


    REBOOTURL="$IP/$KEY/userRpm/SysRebootRpm.htm?Reboot=Reboot"

    echo "Rebooting ..."
    curl -ss "$REBOOTURL" --cookie "${ENC_AUTH_COOKIE}" --referer "http://$IP/$KEY/userRpm/StatusRpm.htm" > /dev/null
    exit 0
else
    echo 'Login failed!'
    echo 'You could have executed the script too often in a short period! In this case try again in 2h.'!'
fi

exit -1

I edit the script to restart it:

IP=${3:-"192.168.1.1"}
USER=${1:-"user"}
PASSWORD=${2:-"password"}

PASSWORD=`echo -n "${PASSWORD}" | md5sum | awk '{ print $1 }'`
auth=`echo -n "${USER}:${PASSWORD}" | base64`
AUTH="Basic $auth"
ENC_AUTH_COOKIE="Authorization="`perl -MURI::Escape -e 'print uri_escape($ARGV[0]);' "${AUTH}"`

RESPOND=`curl -ss "${IP}/userRpm/LoginRpm.htm?Save=Save" --cookie "${ENC_AUTH_COOKIE}"`

re="http\://[0-9A-Za-z.]+/([A-Z]+)/userRpm/Index.htm"
if [[ $RESPOND =~ $re ]]
then
    echo 'Login succesfully'
    KEY=${BASH_REMATCH[1]}


    REBOOTURL="$IP/$KEY/userRpm/SysRebootRpm.htm?Reboot=Reboot"

    echo "Rebooting ..."
    curl -ss "$REBOOTURL" --cookie "${ENC_AUTH_COOKIE}" --referer "http://$IP/$KEY/userRpm/StatusRpm.htm" > /dev/null
    exit 0
else
    echo 'Login failed!'
    echo 'You could have executed the script too often in a short period! In this case try again in 2h.'!'
fi

exit -1

It says me

line 26: unexpected EOF while looking for matching `''
line 30: syntax error: unexpected end of file

and line 26 is

echo 'You could have executed the script too often in a short period! In this case try again in 2h.'!'

and line 30 doesn't exits (29 is exit -1)

Found a typo; however, deleting > /dev/null to see what it runs it says

Login succesfully
Rebooting ...
<hr><h1><B>You have no authority to access this router!</B></h1><hr>%

IP=${3:-"192.168.1.1"}
USER=${1:-"user"}
PASSWORD=${2:-"password"}

PASSWORD=`echo -n "${PASSWORD}" | md5sum | awk '{ print $1 }'`
auth=`echo -n "${USER}:${PASSWORD}" | base64`
AUTH="Basic $auth"
ENC_AUTH_COOKIE="Authorization="`perl -MURI::Escape -e 'print uri_escape($ARGV[0]);' "${AUTH}"`

RESPOND=`curl -ss "${IP}/userRpm/LoginRpm.htm?Save=Save" --cookie "${ENC_AUTH_COOKIE}"`

re="http\://[0-9A-Za-z.]+/([A-Z]+)/userRpm/Index.htm"
if [[ $RESPOND =~ $re ]]
then
    echo 'Login succesfully'
    KEY=${BASH_REMATCH[1]}

    REBOOTURL="$IP/$KEY/userRpm/SysRebootRpm.htm?Reboot=Reboot"

    echo "Rebooting ..."
    curl -ss "$REBOOTURL" --cookie "${ENC_AUTH_COOKIE}" --referer "$REBOOTURL"
    exit 0
else
    echo 'Login failed!'
    echo 'You could have executed the script too often in a short period! In this case try again in 2h.'
fi

exit -1