| append only (a) |
Prevents deletion, but allows appending to a file—for example, if you’ve run chattr +a tester, cat /etc/fstab >> tester would add the contents of /etc/fstab to the end of the tester file. |
| no dump (d) |
Disallows backups of the configured file with the dump command. |
| extent format (e) |
Set with the ext4 filesystem; an attribute that can’t be removed.immutable (i) Prevents deletion or any other kind of change to a file. |
| indexed (I) |
Set on directories for indexing with hashed trees; an attribute that can’t be removed. |