How can I run a function or macro across a folder of files?

Question

Let's say I have a function, named StripWhitespace.

I can run it on a single file by opening the file and running :StripWhitespace.

How can I automatically run that function against a folder of files, and save the results as I go along?

Answer 1

You can use the -c argument to run a command on startup, from vim(1):

   -c {command}
               {command} will be executed after the first  file  has  been
               read.   {command}  is interpreted as an Ex command.  If the
               {command} contains spaces it must  be  enclosed  in  double
               quotes  (this depends on the shell that is used).  Example:
               Vim "+set si" main.c
               Note: You can use up to 10 "+" or "-c" commands.

Example:

vim -c ':call StripWhitespace()' file1 file2

To quit afterwards, add | :wqa:

vim -c ':call StripWhitespace() | :wqa' file1 file2

Answer 2

If you are already in Vim, you can use the :argdo or :bufdo commands to execute a command on every item in the argument list or buffer list, respectively.

e.g. to run a : command on every file in the argument list:

:argdo StripWhitespace

Or to invoke a function from every file in the buffer list:

:bufdo call StripWhitespace()

Or to run macro q on every file in the arguments list:

:argdo normal @q

You can then save all changed buffers with :wall, or save all and quit Vim with :wqall.

If you want to write the files as you go along, you can add in a call to :update, like so:

:argdo s/foo/bar/ge | update

There are various ways you can get the files into Vim in the first place, including:

• Supply parameters to the vim command line: vim * (this adds all the files to the argument list),
• Use the :args command (which supports wildcards and backtick expressions) to populate the argument list, or the :argadd command to add files to it,
• Just open them all manually with :e, :Ex, or a file-opening plugin.