mmapable(1)
mmapable - tell if a file supports the mmap file operation
mmapable FILE...
mmapable will try to mmap(2) each FILE as read only, and for each file will display if this operation succeeded (signaled by a 1 next to the file path) or not (signaled by a 0). If it failed, the error reason provided by errno(3) will be displayed as well on the standard error output.
$ echo test >./file
$ mmapable . /dev/null ./file
mmap: No such device
.: 0
mmap: No such device
/dev/null: 0
./file: 1