The
fbtab
file contains lines which specify how the permissions and ownership of
various system files should be changed based on the user's login device name.
Comments start with a
"#"
and extend to the end of the line.
Blank lines or lines with only a comment are ignored.
All other lines consist of three fields delimited by whitespace.
Login Device
The device you have logged in on (e.g.,
“/dev/ttyv0)”.
File Permission
An octal permission number (0600), as used by
chmod(2).
Other devices
The final field is a colon
("\&:")
delimited list of devices (e.g.,
“/dev/console:/dev/fd0a)”.
All device names are absolute paths.
A path that ends in
“/\&*”
refers to all directory entries except
“\&.”
and
“\&.\&.”.
The
fbtab
file is used by
login(1)
to
chown(2)
the specified files to the user who has performed a login.
Additionally,
chmod(2)
is used to set the devices to the specified permission.
When a user logs out,
init(8)
is responsible for performing the inverse operation, which results in
the files once again belonging to root.