How to stop VIM from adding a newline at end of file?

Question

And for vim 7.4+ you can use (preferably on your .vimrc) (thanks to 罗泽轩 for that last bit of news!):

:set nofixendofline

Now regarding older versions of vim.

Even if the file was already saved with new lines at the end:

vim -b file and once in vim:

:set noeol
:wq

done.

alternatively you can open files in vim with :e ++bin file

Yet another alternative:

:set binary
:set noeol
:wq

see more details at Why do I need vim in binary mode for 'noeol' to work?

Add the following command to your .vimrc to turn of the end-of-line option:

autocmd FileType php setlocal noeol binary fileformat=dos

However, PHP itself will ignore that last end-of-line - it shouldn't be an issue. I am almost certain that in your case there is something else which is adding the last newline character, or possibly there is a mixup with windows/unix line ending types (\n or \r\n, etc).

Update:

An alternative solution might be to just add this line to your .vimrc:

set fileformats+=dos

There is another way to approach this if you are using Git for source control. Inspired by an answer here, I wrote my own filter for use in a gitattributes file.

To install this filter, save it as noeol_filter somewhere in your $PATH, make it executable, and run the following commands:

git config --global filter.noeol.clean noeol_filter
git config --global filter.noeol.smudge cat

To start using the filter only for yourself, put the following line in your $GIT_DIR/info/attributes:

*.php filter=noeol

This will make sure you do not commit any newline at eof in a .php file, no matter what Vim does.

And now, the script itself:

#!/usr/bin/python

# a filter that strips newline from last line of its stdin
# if the last line is empty, leave it as-is, to make the operation idempotent
# inspired by: https://stackoverflow.com/questions/1654021/how-can-i-delete-a-newline-if-it-is-the-last-character-in-a-file/1663283#1663283

import sys

if __name__ == '__main__':
    try:
        pline = sys.stdin.next()
    except StopIteration:
        # no input, nothing to do
        sys.exit(0)

    # spit out all but the last line
    for line in sys.stdin:
        sys.stdout.write(pline)
        pline = line

    # strip newline from last line before spitting it out
    if len(pline) > 2 and pline.endswith("\r\n"):
        sys.stdout.write(pline[:-2])
    elif len(pline) > 1 and pline.endswith("\n"):
        sys.stdout.write(pline[:-1])
    else:
        sys.stdout.write(pline)

I have not tried this option, but the following information is given in the vim help system (i.e. help eol):

'endofline' 'eol'   boolean (default on)
            local to buffer
            {not in Vi}

When writing a file and this option is off and the 'binary' option
is on, no <EOL> will be written for the last line in the file.  This
option is automatically set when starting to edit a new file, unless
the file does not have an <EOL> for the last line in the file, in
which case it is reset.  

Normally you don't have to set or reset this option. When 'binary' is off the value is not used when writing the file. When 'binary' is on it is used to remember the presence of a for the last line in the file, so that when you write the file the situation from the original file can be kept. But you can change it if you want to.

You may be interested in the answer to a previous question as well: "Why should files end with a newline".