5 ms·

But the superuser privileges should have overridden such directory permissions, even 25 years ago....

• DmitriRavinoff 12y ago
  Yes, but if you can't run the chmod binary...
  • fjarlq 12y ago
    No, root can still run chmod, because its superuser privileges override the new restrictive directory perms. That was my point. Maybe the original problem was actually "chmod a-rwx /bin/chmod" ... That would mean even the superuser couldn't execute /bin/chmod anymore, so you'd have to do something more creative to reset the executable bit on /bin/chmod. Like compile a C program that calls the chmod system call, or: mv /bin/chmod /bin/chmod.orig cp -p /bin/ls /bin/chmod cp /bin/chmod.orig /bin/chmod
    • pantalaimon 12y ago
      > Like compile a C program that calls the chmod system call The compiler wouldn't be executable anymore either
      • claviola 12y ago
        Yes, it would. Like he said, you can still run it unless you specifically removed its permissions.
  • mtdewcmu 12y ago
    The explanation for what made him type that is what interests me. It would be like accidentally cutting your left hand clean off with a steak knife while you were eating dinner.
    • johnchristopher 12y ago
      My bash is set to use vim bindings (set -o vi) and I constantly loop through commands. I am guilty of doing this while sleepy and sometimes I think I have cd to another directory when in fact I have not. I rm-ed (too) many things that way.
      • mtdewcmu 12y ago
        I gave the vi mode a very short try, but it doesn't seem to make as much sense in a shell. If it has you accidentally deleting things, you might want to ask how much is it really worth. In vim you can undo.
  • r4um 12y ago
    One can use the shared library loader to invoke binaries that do not have executable bit set, comes in handy once in a while. $ cp /bin/chmod . $ chmod -x ./chmod $ /lib/ld-2.19.so ./chmod ./chmod: missing operand Try './chmod --help' for more information.