Put all words separated by commas on a new line

Question

I am attempting to write a script to pull all words separated by commas on a new line from a text file that contains the following:

HELLO,DOCTOR,NAME,CONTINUE,YESTERDAY,TOMORROW

Answer 1

Demonstrating how to apply the individual linked-duplicate questions, each of which addresses a separate element of this question:

IFS=, read -r -a words <file  # from duplicate "How do I split a string on a delimiter?"
printf '%s\n' "${words[@]}"   # from duplicate "Print array elements on separate lines"

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Similarly, the approach given in How do I replace : characters with newline? works just as well with , as with : --

tr ',' '\n' <file