cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | head -n 1 #get only one line (hash)
cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w 32 | tee file.txt #keep output unique lines till you stop it

sort file.txt | uniq > ufile.txt   # remove duplicates lines from a file
wc -l #get number of lines in a file