columnt then prints the table, changing the spacing so that the first column takes the same amount of space in every line, the second column takes the same amount of space in every line, etc.
In the columnt output, all columns except the last are right-justified; the last column is left-justified. There are two spaces between adjacent columns.
columnt needs enough memory to read the entire input. Other than this, it has no limits on line length or on the number of columns.