Comprehensive difference in read file to variable at once and by line

Reading by lines: for ln in lines("file.txt"): echo ln Run

Comprehensive difference in read file to variable at once and by line

How're syntax differences in read file to variable by at once i.e. slurping it and line by line As I know/think this is only slurping it > `var whole = readFile(textfile)` please put the clear, correct comparative ones here