Lost all my /usr/lib files in trial so solve glib dependency

Question

Hi,
Failing to upgrade my Arch_X86-64 system due to glibc dependencies, I've followed an advice in the forum and tried to move (as root) all files in usr/lib to a (temporary, initially empty) directory I've created. Now I can't see any files, neither in /usr/lib nor in the backup direvtory (see terminal output below).
Please advise how to restore my system?
thanks
Miki Badt
copy of terminal output
root /usr/lib # mv * /lib_back/
root /usr/lib # pacman -Syu
pacman: error while loading shared libraries: libalpm.so.7: cannot open shared object file: No such file or directory
root /usr/lib # mv /lib_back/* .
mv: error while loading shared libraries: libacl.so.1: cannot open shared object file: No such file or directory
root /usr/lib # ls
ls: error while loading shared libraries: libcap.so.2: cannot open shared object file: No such file or directory
root /usr/lib # cd /lib_back/
root /lib_back # ls
ls: error while loading shared libraries: libcap.so.2: cannot open shared object file: No such file or directory
root /lib_back # cd /usr/lib
root /usr/lib # ls
ls: error while loading shared libraries: libcap.so.2: cannot open shared object file: No such file or directory
root /usr/lib #

Answer 1

boot from arch iso and chroot into your system
(eg. mount /dev/sda1 /mnt && chroot /mnt)
and revert your commands, simple as that !