HackerRank Tr Command #2 problem solution

In this HackerRank 'Tr' Command #2 problem-solution In this challenge, we practice using the tr command because it is a useful translation tool in Linux.

In a given fragment of text, delete all the lowercase characters a - z.

Input Format

A block of ASCII text.

Output Format

Delete all the lowercase characters in the given block of text.

Problem solution.

tr -d [a-z]

Second solution.

tr -d '[:lower:]'

Third solution.

read A
while [[ -n "$A" ]] 
do
  echo "$A" | tr -d [a-z]
  read A
done
echo ""