mkfifo creates the fifos requested, in the order specified, using mode
0666 modified by the current
umask(2).
The options are as follows:
-m
Set the file permission bits of newly-created fifos to
mode. The mode is specified as in
chmod(1). In symbolic mode strings, the “+” and “-” operators are interpreted relative to an assumed initial mode of “a=rw”
mkfifo requires write permission in the parent directory.
mkfifo exits 0 if successful, and >0 if an error occurred.