这应该做你想做的
:set shellslash
帮助 ( :h shellslash
) 复制在下面
'shellslash' 'ssl' 'noshellslash' 'nossl'
'shellslash' 'ssl' boolean (default off)
global
{not in Vi} {only for MSDOS, MS-Windows and OS/2}
When set, a forward slash is used when expanding file names. This is
useful when a Unix-like shell is used instead of command.com or
cmd.exe. Backward slashes can still be typed, but they are changed to
forward slashes by Vim.
Note that setting or resetting this option has no effect for some
existing file names, thus this option needs to be set before opening
any file for best results. This might change in the future.
'shellslash' only works when a backslash can be used as a path
separator. To test if this is so use:
if exists('+shellslash')