egrep '\<(Königst|T)ochter\>' frosch.txt
grep :/bin/bash$ /etc/passwd
k='[^aeiou]*'
grep -i ^${k}a${k}e${k}i${k}o${k}u${k}$ /usr/share/dict/words
egrep '(\<[[:alpha:]]{4,}\>).*\<\1\>' frosch.txt