Zonsopgang:

curl -s http://zonsondergang.info | grep -o '<span class="vandaag ">.............</span>' | grep -o "..:.. - ..:.." | cut -c 1-5

Zonsondergang:

curl -s http://zonsondergang.info | grep -o '<span class="vandaag ">.............</span>' | grep -o "..:.. - ..:.." | cut -c 9-13

Voorbeeld uitvoering tussen zonsopgang en zonsondergang:

sunrise=$(curl -s http://zonsondergang.info | grep -o '.............' | grep -o "..:.. - ..:.." | cut -c 1-5)
sunset=$(curl -s http://zonsondergang.info | grep -o '.............' | grep -o "..:.. - ..:.." | cut -c 9-13)

begin=$(date --date="$sunrise" +%s)
end=$(date --date="$sunset" +%s)
now=$(date +%s)

if [ "$begin" -le "$now" -a "$now" -le "$end" ]; then
    echo Checked daylight.. sun is still up..
    echo Doing some meaningful task that can stand daylight..
fi