Sometimes it is necessary to prevent all users including root from deleting a file. This is often done by changing the file attributes on a Linux file system. The tool used to change file attributes in Linux and other Unix systems is chattr and the tool used to view the newly set attributes is lsattr.
The format of a symbolic mode is +-=[acdeijstuADST]. The format of a symbolic mode is +-=[acdeijstuADST] and they select the new attributes for
the files.
- The operator ‘+’ causes the selected attributes to be added
to the existing attributes of the files - ‘-’ causes them to be removed
- ‘=’ causes them to be the only attributes that the files have.
See explanation of all letters used below: