A Sticky bit is a file/directory permission feature in Unix.
Sometimes when we give write permission to another user then that user can delete the file without the owner knowing about it. To prevent such an accidental deletion of file we use sticky bit.
When we mark a file/directory with a sticky bit, no user other than owner of file/directory gets the privilege to delete a file/directory.
To set the sticky bit we use following command:
% chmod +t filename
When we do ls for a file or directory, the entries with sticky bit are listed with letter t in the end of permissions.
E.g. % ls –lrt
-rwxrwxrwt 5 abc abc 4096 Jan 1 10:10 abc.txt
To remove the sticky bit we use following command:
% chmod –t filename