POSIX portable file names were defined not to have spaces, and just contain '[[:alnum:]_./]'. The findnl script as part of fslint identifies problematic patter

POSIX portable file names were defined not to have spaces, and just contain '[[:alnum:]_./]'. The findnl script as part of fslint identifies problematic patterns, and has 4 levels of stringency, with "POSIX" being the most stringent. https://github.com/pixelb/fslint/blob/master/fslint/findnl https://github.com/pixelb/fslint/blob/master/fslint/findnl