What is the output of the following command? echo "Hello World" | tr -d aieou

Hello World would be the output only if no characters were deleted, but tr -d aieou explicitly removes lowercase vowels present in the string.

eoo represents only the deleted vowels themselves, not the remaining characters that tr outputs after deletion.

tr -d aieou instructs tr to delete any character that appears in the set {a, i, e, o, u}. Applying this to 'Hello World' removes 'e' (from Hello), 'o' (from Hello), and 'o' (from World), leaving 'Hll Wrld'. Uppercase letters and spaces are not in the delete set, so they are preserved.

eoo Hll Wrld incorrectly combines the deleted characters with the remaining output; tr outputs only the surviving characters, not both.