ctags

download from here . intall it:

$ tar -xzvf ctags-5.6.tar.gz
$ cd ctags-5.6
$ make
$ sudo make install   

use it: go to directory

$ ctags -R

ctrl+] go to function definition. ctrl+t go back.

taglist

download from here.

add these in .vimrc

let Tlist_Show_One_File=1
let Tlist_Exit_OnlyWindow=1

use command with :Tlist in vim.

winmanager

download from here.

add these in .vimrc

let g:winManagerWindowLayout='FileExplorer|TagList'
nmap wm :WMToggle<cr>

restart vim and type ‘wm’ in normal state

grep

download form here.

add in .vimrc

nnoremap <silent> <F3> :Grep<CR>

then you can use F3 to search your word.