1.  egrep '^a.*' dictionary.txt
2.  egrep '^[Aa].*' dictionary.txt
3.  egrep '^[a-zA-Z]{4}$' dictionary.txt
4.  egrep '^a[a-zA-Z]{3}$' dictionary.txt
5.  egrep '^[a-zA-Z]{4}[a-zA-Z]*$' dictionary.txt
6.  egrep '.*[A-Z].*$'  dictionary.txt
7.  egrep '^[a-z].*[A-Z].*$'  dictionary.txt
8.  egrep '[a-z]*[A-Z][a-z]*[A-Z][a-z]*$'  dictionary.txt
9.  egrep '^[^a].*[^a]$'  dictionary.txt
10. egrep '^[aAeEiIoOuU].*[aAeEiIoOuU]$'  dictionary.txt
11. egrep '^[^aAeEiIoOuU].*[^aAeEiIoOuU]$'  dictionary.txt
12. egrep '^.*[aA].*[eE].*[iI].*[oO].*[uU].*$'  dictionary.txt
13. egrep '^.*[jJ].*[Dd].*[Bb].*$'  dictionary.txt
14. egrep '^[jJeEsSiIcCaA]*$'  dictionary.txt