There are certain occassions when you want to make a special non-linear selection in your text editor. You may for example want to select a column of all first characters in a long list. You can select each letter manually by pressing the Apple (Cmd) key, but this is tedious work.
To avoid such waste of time, you can press and hold the Alt (Option) key, click and drag your cursor to select text freely without the constrains of regular text selection. This works in most text editors, such as Textedit and TextWrangler. This feature makes certain programming tasks extremely easy if you use such a selection in combination with Find and Replace command.