Once upon a time, Suvayu Ali <fatkasuvayu+linux@xxxxxxxxx> said: > I have never properly understood the leading bit in permissions. (the 0 > in the 0755) Could you point me to some easily understandable resource? The leading 3 bits is essentially an add-on to each of the user, group, and other sections. For user and group, the corresponding bit is the set-id bit. For executable filess with the set-user-id bit (e.g. 4xxx) or set-group-id bit (e.g. 2xxx) set, the executable runs as the files owner or group, not the calling user or group. For directories, set-group-id means that new entries in that directory inherit the group from the directory instead of the calling group. The bit corresponding to other (e.g. 1xxx) is called the "sticky" bit. On directories (such as /tmp), it means that only users/groups with permissions to a file can delete it. In old Unix, the sticky bit on an executable changed the way the kernel paged it into and out of RAM, but I don't believe Linux uses it. -- Chris Adams <cmadams@xxxxxxxxxx> Systems and Network Administrator - HiWAAY Internet Services I don't speak for anybody but myself - that's enough trouble. -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
