- setuid bit. Denoted by
S(files) in the permissions block of
lsresults, it only applies to executable files — it just specifies which user (u+s) / group (ug+g) the process should run as when executed.
To clear this bit, simply run
chmod -s yourfile.txt.
- sticky bit. Denoted by
S, due to setuid’s precedence), it’s usually used on directories to control a hierarchy of permissions. E.g., to share a temporary directory between users, but limit the control each user has on another user’s files in that directory.
To clear, run
chmod -t tmp/.
- file acl. Denoted by a trailing
+ (plus sign), you can show more details by calling
Clear the custom ACL settings with
setfacl -b index.html.
- selinux. Denoted by a trailing
ls -Z will show the full story.
Remove this setting with
sudo setfattr -x security.selinux favicon.ico.
getfattr -d favicon.ico does not do what it says it will do, i.e., print out
security.selinux="...", but it has a funny name, and explicity using
getfattr -n security.selinux works, so perhaps we can forgive it.)
It seems that
chcon (“change context”, like
chmod “change modifiers”, for example), the dedicated tool for SELinux context configuration, cannot remove the file attribute.