squizlabs/PHP_CodeSniffer — pull request #226 by jedgell (2014-08-10 20:55:41+00:00)
Title: Bug #20367 --ignore does not accept pipes in <patterns>

Backticks (`), in *nix systems, in any case, are not valid filename
or directory name characters. Besides which, I do not believe they have
a special meaning in processing regular expressions.