root can't write or modify /bin, /usr/bin, /sbin, /usr/sbin
On a debian system, I'm logged in as root.
I cannot create any files in
I can create files in
/usr/share, etc, etc.
All these directories are owned by root and have permission 755.
The partition is not full.
touch /usr/bin/foo touch: cannot touch `/usr/bin/foo': Permission denied
(and the file does not already exist)
chmod fail on directories named "
bin" or "
sbin", but not on other directories.
You might want to check the file attributes using
lsattr. It's well possible that those directories have been made "immutable" to prevent alteration, even by root.
Sounds like those directories where you can't change anything were mounted read-only.
You might want to check the output of
To add on to Manni's answer, often times a file system will be mounted read only if there was an error during a file system check. You may want to check your boot logs to see if there were errors.