The easiest way is learning what shift does in Bash, like another comment said, but if you're not going to do that: - C also has functions called getc() and un

The easiest way is learning what shift does in Bash, like another comment said, but if you're not going to do that: - C also has functions called getc() and ungetc(), and they're analogous. - "Doing" and "undoing" are actually the same in some sense: doing causes information loss, undoing causes information gain.