In addition to statox's methods, you can:
- Position the cursor at the beginning of the leading whitespace and type
dw - Position the cursor anywhere in the leading whitespace and type
diw - Position the cursor at the first non-space character of the line and type
d0 - Visually select all the lines you want to move left, e.g., by typing
Von the first line and moving the cursor to the last line, then executing:left
Update
What I actually usually do in such cases is:
- Visually select all the lines as above, type
<to move them left by one shiftwidth, then type.until they're shifted all the way to the left margin.