Mac OS X Panther in a Nutshell, 2nd Edition

Name

mark

Synopsis

[address] ma 
                     char
                  

Mark the specified line with char, a single lowercase letter. Return later to the line with 'char. vim also uses uppercase and numeric characters for marks. Lowercase letters work the same as in vi. Uppercase letters are associated with filenames and can be used between multiple files. Numbered marks, however, are maintained in a special viminfo file and can’t be set using this command. Same as k.