Author: Ruwantha Nissanka

In our previous post, we have discussed about how to set the standard file permissions in our linux system. In this guide we will see how to set more advanced permissions to our files. sticky bit on directory You can set the sticky bit on a directory to prevent users from removing files that they do not own as a user owner. The sticky bit is displayed at the same location as the x permission for others. The sticky bit is represented by a t (meaning x is also there) or a T (when there is no x for others). The sticky bit can also be set with octal permissions, it is binary 1 in the first of four triplets. You will typically find the sticky bit on the /tmp directory. setgid bit on directory setgid can be used on directories to make sure that all files inside the directory are owned by the group owner of the directory. The setgid bit is displayed at the same location as the x permission for group owner. The setgid bit is represented by an s (meaning x is also there) or a S (when there is no x for the group owner). As this example shows, even though root does not belong to the group proj55, the files created by root in /project55 will belong to proj55 since the setgid is...

Linux operating system allows multiple users to work on the same system simultaneously without disrupting each other. Because of this feature, Individuals sharing access to files pose a risk exposing classified information or even data loss if other users access their files or directories. To address this, we can specify how much power each user has over a given file or directory by setting file permissions. rwx The nine characters following the file type denote the permissions in three triplets. A permission can be r for read access, w for write access, and x for execute. You need the r permission to list (ls) the contents of a directory. You need the x permission to enter (cd) a directory. You need the w permission to create files in or remove files from a directory We already know that the output of ls -l starts with ten characters for each file. This screenshot shows a regular file (because the first character is a – ). permission examples Some example combinations on files and directories are seen in this screenshot. The name of the file explains the permissions. To summarise, the first rwx triplet represents the permissions for the user owner. The second triplet corresponds to the group owner; it specifies permissions for all members of that group. The third triplet defines permissions for all other users that are not the...