the truncation is a poor example. - it creates the file if it does not exist, not merely truncate. as a tutorial kind of blog post this incomplete description

the truncation is a poor example. - it creates the file if it does not exist, not merely truncate. as a tutorial kind of blog post this incomplete description matters IMO. - it would work the same without the colon (similar for default variable assignment examples). we generally strive not to have "extra" things, like useless use of cat. - educationally it's useful to demonstrate that redirection, like parameter expansion, works before the command executes (the null command in this case), but the article doesn't explain that at all! otherwise i <3 this article. some uses of colon i had never thought of or seen before. like file truncation, not sure i'd use them but it was cool to see them.