check to see whether a file exists in cmd.exe

if-exists.cmd

if exist {insert file name here} (
    rem file exists
) else (
    rem file doesn't exist
)

# or on a single line (if only a single action needs to occur):
if exist {insert file name here} {action}

# a quick little example testing for both files and/or directories:
md foo 
echo.>bar 
for %I in (foo bar xyz) do @( 
  if exist %I ( 
    if exist %I\nul ( 
      echo -- %I is a directory 
    ) else ( 
      echo -- %I is a file 
    ) 
  ) else ( 
    echo -- %I does not exist 
  ) 
)