Summary

chattr is use to change file attributes on a Linux file system.

The format of a symbolic mode is +-=[acdeijstuADST].

The operator ‘+’ causes the selected attributes to be added to the existing attributes of the files; ‘-’ causes them to be removed; and ‘=’ causes them to be the only attributes that the files have.

The letters ‘acdeijstuADST’ select the new attributes for the files:

• append only (a)
• compressed (c)
• no dump (d)
• extent format (e)
• immutable (i)
• data journalling (j)
• secure deletion (s)
• no tail-merging (t)
• undeletable (u)
• no atime updates (A)
• synchronous directory updates (D)
• synchronous updates (S)
• top of directory hierarchy (T).

Usage

Make a file immutable

Making a file immutable means it cannot be changed.

$ chattr +i <filename>

Remove file immutable

$ chattr -i <filename>