utility to look up public transport connections directly using a shell or launcher like dmenu.

bahn.bash

#!/bin/bash

# Example usage:
# ./bahn berlin_hbf frankfurt_hbf
# ./bahn berlin_hbf frankfurt_hbf @23h23 localonly    # arrive at 23h23 in two days, not using “I’m broke” mode (no EC,IC,ICE)

# bahn v0.2.1 (2012-03-16)
#
# 0.2.1 fix automatic selection of tomorrow if time given has
#       already passed
# 0.2   times may be written like '13h37'
#       new parameter 'localonly' to exclude EC, IC, ICE
#       be more intelligent about the given time: detect if
#           'tomorrow at that time' is meant and select
#           tomorrow if no date is given.
# 0.1   initial release

if (( "$#" < 2 )); then
    echo "USAGE: bahn from to [[@][h]h:mm] [+n|yyyy-mm-dd] [localonly]"
    echo
    echo "If time [h]h:mm is omitted 'now' is assumed."
    echo "Prepend an '@' if you want to specfiy 'time"
    echo "of arrival'. If not it's 'time of depature'."
    echo
    echo "If date is omitted 'today' is assumed.  You"
    echo "can either specify a full date in the 'yyyy"
    echo "-mm-dd'  format or use '+n' for n days from"
    echo "today, e.g. +1 for tomorrow."
    echo
    echo "Add localonly as last argument if you want"
    echo "to exclude EC, IC and ICE connections."
    echo
    echo "For your convenience underscores will be re-"
    echo "placed with spaces. This will be useful when"
    echo "using bahn with e. g. dmenu,  which does not"
    echo "support grouping with quotes."
    exit
fi

echo

start=${1//_/ }
dest=${2//_/ }

echo "starting station:    ${start}"
echo "destination station: ${dest}"

# see if any of the arguments is 'local only' and remove it from
# the input args since it may appear anywhere
if [ "${!#}" = "localonly" ]; then
    localonlyurl="&REQ0JourneyProduct_prod_list=4:0001111111000000"
    echo "excluded trains:     EC, IC, ICE"
fi

# extract time information
if [[ "${3:0:1}" == "@" ]] ; then
    timesel="arrive"
    time="${3:1:5}"
    timedesc="time of arrival:    "
else
    timesel="depart"
    time="${3:0:5}"
    timedesc="time of departure:  "
fi
# remove the 'h' in time, if it was used
time=${time//h/:}

# syntax check input. Otherwise bahn.de will annoy the user
# with an extra step.
if [[ $time =~ ^[0-9]{1,2}[:h][0-9]{2}$ ]]; then
    echo "${timedesc} ${time}"
    timeurl="&time=${time}"
else
    # do not whine about no input or 'localonly'
    if [[ ${#time} > 0 ]] && [[ "${time}" -ne "localonly" ]]; then
        echo "WARNING:"
        echo "Could not parse given time; it should be"
        echo "in the [@][h]h:mm format. Your input was:"
        echo $3
    fi
fi

# find correct date, if there is any input
if [[ ${#4} > 0 ]] && [[ "$4" -ne "localonly" ]]; then
    if [[ $4 =~ ^20[0-9]{2}-[0-9]{2}-[0-9]{2}$ ]]; then
        dateurl="&date=${4:8:2}.${4:5:2}.${4:0:4}"
        echo "date of travel:      ${4:0:4}-${4:5:2}-${4:8:2}"
    elif [[ $4 =~ ^\+[0-9]+$ ]]; then
        d=$(date --date "${4} days" +%d.%m.%Y)
        dateurl="&date=${d}"
        d=$(date --date "${4} days" +%Y-%m-%d)
        echo "date of travel:      ${d}"
    else
        echo "WARNING:"
        echo "Could not parse given date; it should be"
        echo "in either of the following formats:"
        echo "\tyyyy-mm-dd"
        echo "\t+n"
        echo "Your input was:"
        echo ${4}
    fi
# if a time was given but no date has been specified and the time
# is in the past (e.g. 9:00 is given, but it’s 11:30 already) then
# automatically set to search for the next day.
# Note the -gt: For some reason > doesn’t work here.
elif [[ ${#timeurl} > 0 ]] && [[ $(( $(date "+%s") - $(date --date="$time" "+%s") )) -gt 0 ]]; then
    d=$(date --date "1 days" +%d.%m.%Y)
    dateurl="&date=${d}"
    d=$(date --date "1 days" +%Y-%m-%d)
    echo "date of travel:      ${d}   (assuming you meant tomorrow)"
fi

url="http://reiseauskunft.bahn.de/bin/query.exe/dn?start=1&S=${start}&Z=${dest}&timesel=${timesel}&optimize=1&tariffTravellerType.1=E&tariffTravellerReductionClass.1=0&tariffTravellerAg${timeurl}${dateurl}${localonlyurl}"
# very simple way to encode spaces, if there are any. Still won’t
# output correctly encoded URL if start or destination contain
# non URL chars.
url=${url// /%20}


echo
echo
echo "${url}"
echo
echo "Opening browser…"
x-www-browser "${url}"
echo
echo "Sang ju vor trevelling wifs deutsche bahn."