Set the mark
marks the current cursor location with the designated letter. lowercase marks are local to each individual buffer. uppercase marks are globally accessible.
Two Normal mode commands
moves to the line where a mark was set, positioning the cursor on the first non-whitespace character.
moves the cursor to the exact position where a mark was set, restoring the line and the column at once.
Note: mm, ``m`: make a handy pair. They set the mark m and jump to it.
Vim's Automatic Marks
