Default format is PNG, change it to any of the following:

defaults write com.apple.screencapture type JPG

defaults write com.apple.screencapture type TIFF

defaults write com.apple.screencapture type GIF

defaults write com.apple.screencapture type PDF

defaults write com.apple.screencapture type PNG

First encountered here.

int x = 11;

[NSString stringWithFormat:@"%03i", x];
// @"011"

[NSString stringWithFormat:@"%+5i", x];
// @"+++11"

[NSString stringWithFormat:@"%+05i", x];
// @"+0011"

And not really like that. 381. I'll still have to learn a lot of C.