The PadLeft(s, width) command adds spaces to the left of the string s to produce a string of length equal to width. If width is less than or equal to the length of s, then s is returned unchanged.

The PadRight(s, width) command adds spaces to the right of the string s to produce a string of length width. If width is less than or equal to the length of s, then s is returned unchanged.

The Center(s, width) command adds spaces to both ends of the string s to produce a string of length width. If width - length(s) is even, then an equal number of spaces are added to the left and right ends of s. If width - length(s) is odd, then the extra space is added to the left of s.

The StringTools[TrimLeft], StringTools[TrimRight] and StringTools[Trim] commands are approximate inverses of PadLeft, PadRight and Center, respectively.