ag ignore

IGNORING FILES
       By default, ag  will  ignore  files  whose  names
       match   patterns  in  .gitignore,  .hgignore,  or
       .ignore. These  files  can  be  anywhere  in  the
       directories  being  searched.  Binary  files  are
       ignored by default as well. Finally, ag looks  in
       $HOME/.agignore for ignore patterns.

       If  you  want to ignore .gitignore and .hgignore,
       but still take .ignore into account, use -U.

       Use the -t option to search all text files; -a to
       search all files; and -u to search all, including
       hidden files.