wordlist.txt

Remove duplicates

awk '!(count[$0]++)' old.txt > new.txt 

Sort wordlist by length

awk '{print length, $0}' old.txt | sort -n | cut -d " " -f2- > new.txt 

Sort by alphabetical order

sort old.txt | uniq > new.txt 

Merge multiple text files into one

cat file1.txt file2.txt > combined.txt

Remove all blank lines

egrep -v "^[[:space:]]*$" old.txt > new.txt