Accept ČD Wifi on the command line (if you hate clicking). http://cdwifi.cz

cdwifi.sh

#!/bin/bash
# Accept CD Wifi (Czech railways) on the command line (if you hate clicking).
# http://cdwifi.cz
#
# Put the script to ~/bin/cdwifi and make sure that export it's on the path: PATH=$PATH:~/bin
# Note that if you have a custom DNS set (eg. 8.8.8.8 or 1.1.1.1) they don't resolve
# cdwifi.cz. If you don't want to use their DNS set via DHCP for all your traffic
# the workaround here is to query their DNS server at the gateway just
# for this request.
#
# It works on Mac and should also work on Linux.

if [[ "$OSTYPE" == "linux-gnu"* ]]; then
    # Linux
    GATEWAY=$(route -n |grep '^0.0.0.0' |sed 's/ \+/ /'|cut -d' ' -f 2)
elif [[ "$OSTYPE" == "darwin"* ]]; then
    # Mac OSX
    GATEWAY=$(route get default|grep gateway:|sed 's/.*: //')
fi

if [ ! -z "$GATEWAY" ]; then
    HOST=$(nslookup cdwifi.cz $GATEWAY|grep 'Address: '|sed 's/.*: //')
else
    echo "Warning: can't lookup IP address of cdwifi.cz"
    HOST=cdwifi.cz
fi

curl -s \
  -o /dev/null \
  -w "%{http_code}\n" \
  -b 'user.email=eula@accepted' \
  -H 'Host: cdwifi.cz' \
  http://${HOST}/portal/api/vehicle/gateway/user/authenticate?url=http://cdwifi.cz/ \
  | grep -q 307 \
  && echo OK \
  || echo Error

Thank you good sir, this helped me connect to wifi on the train