func! s:sync(bang, bundle) abort
        let git_dir = expand(a:bundle.path().'/.git/')
        if isdirectory(git_dir)
                if !(a:bang) | return 0 | endif
                let cmd = 'git pull'
                if (has('win32') || has('win64'))
                        "let cmd = substitute(cmd, '^cd ','cd /d ','')  " add /d switch to change drives
                        let cmd = '"'.cmd.'"'                          " enclose in quotes
                endif
                "cd to bundle path"
                cd `=a:bundle.path()`
                let l:result = s:system(cmd)
                if l:result =~ "^Already up-to-date."
                        return 0
                else
                        return 1
                endif
        else
                let cmd = 'git clone '.a:bundle.uri.' '.a:bundle.path()
                call s:system(cmd)
                return 1
        endif
endf