Automatically Update Copyright Notice in Files

Especially when editing source code, there is often a copyright notice embedded in the file. Insert the following in a vimrc file to automatically update this copyright notice in ALL FILES when writing them (note that ^V must be replaced by an actual CTRL-V character, or CTRL-Q for the default Windows mapping, and ^M must be replaced by an actual CTRL-M character):

" Automatically update copyright notice with current year
autocmd BufWritePre * 
      \ if &modified |
      \   exe "normal :g#\\(\\c^V169\\|©\\) \\?Copyright#s#\\(".strftime("%Y")."\\)\\@!\\([0-9]\\{4\\}\\)\\(-[0-9]\\{4\\}\\)\\?#\\2-".strftime("%Y")."^M" |
      \ endif

This replaces yyyy or yyyy-yyyy with yyyy-<current year> on any line in the file containing "© copyright" or "&copy; copyright" with or without the space in a case-insensitive manner. It only does this if the file has been modified.

An explaination of the command string follows:

• g#\\(\\c^V169\\|©\\) \\?Copyright#s# - search and replace only on a line matching case-insensitive copyright notice patten. I use '#' rather than the customary '/' to avoid confusion with all the '\' characters. The ^V169 is to insert a © symbol. The command didn't work if I just placed it in there.
• \\(".strftime("%Y")."\\)\\@! - only match when the entire match does not consist of the current year (e.g. if the year is 2007, don't update a notice reading © 2007).
• \\([0-9]\\{4\\}\\) - matches a 4-digit year and allows a backreference to it for use in the replace text.
• \\(-[0-9]\\{4\\}\\)\\? - optionally match an ending year, e.g. the "-2006" in "© 2000-2006".
• \\2-".strftime("%Y") - replace the found text with the second backreference (first year in the copyright), a hyphen, and the current year.