.TH DIR 5 .SH NAMEdir \- format of directories.SH SYNOPSIS.B #include <sys/dir.h>.SH DESCRIPTIONA directorybehaves exactly like an ordinary file, save that nouser may write into a directory.The fact that a file is a directory is indicated bya bit in the flag word of its i-node entrysee,.IR filsys (5).The structure of a directory entry as given in theinclude file is:.RS.ta 8n +6n.PP.nf.so /usr/include/sys/dir.h.fi.RE.PPBy convention, the first two entries in each directoryare for `\fB.\fR' and `\fB..\fR'.  The first is an entry for thedirectory itself.  The second is for the parentdirectory.The meaning of `\fB..\fR' is modified for the root directoryof the master file system and for the root directories of removablefile systems.In the first case, there is no parent, and in the second,the system does not permit off-device references.Therefore in both cases `\fB..\fR' has thesame meaning as `\fB.\fR'..SH "SEE ALSO"filsys(5)