When libc.so.6 goes missing, your Linux system enters a critical state where most dynamically linked binaries (including ln itself) become unusable. This happens because:

Glibc functions resolve through this symbolic link
Core utilities like ln, ls, and mv depend on dynamic linking
Only shell builtins and statically compiled binaries remain operational



Before attempting symlink recreation, verify available tools:
# Check available commands
type -a echo
type -a printf
type -a exec

Common functional builtins include: echo, printf, exec, read, and test.
For systems with Perl still accessible (sometimes statically compiled):
exec perl -e 'symlink("/lib/x86_64-linux-gnu/libc-2.31.so", "/lib/x86_64-linux-gnu/libc.so.6")'

If Perl isn't available, try Python (if installed statically):
exec python -c 'import os; os.symlink("/lib/x86_64-linux-gnu/libc-2.31.so", "/lib/x86_64-linux-gnu/libc.so.6")'

When only shell builtins remain, use exec with inline assembly:
exec 3>&1
(printf '\x01\x00\x00\x00\x00\x00\x00\x00/lib/x86_64-linux-gnu/libc-2.31.so\x00/lib/x86_64-linux-gnu/libc.so.6\x00' > /proc/self/fd/3) 1>/dev/null
exec 3>&-

Note: This requires knowing the exact syscall number for symlinkat on your architecture.
After successful symlink creation, verify with:
ls -l /lib/x86_64-linux-gnu/libc.so.6

Expected output:
lrwxrwxrwx 1 root root 19 Jan 1 00:00 /lib/x86_64-linux-gnu/libc.so.6 -> libc-2.31.so


Keep a statically compiled busybox binary in /rescue
Document critical symlinks: ls -l /lib*/*.so* > /root/lib_links.txt
Consider using LD_PRELOAD hooks for critical libraries





When the libc.so.6 symlink gets accidentally deleted, your Linux system enters a dangerous state where most binaries (including ln itself) become unusable. This happens because:

Glibc dynamic loader relies on this symlink
90%+ of system utilities depend on libc
Even basic package managers may fail



Standard solutions like ln -s /lib/x86_64-linux-gnu/libc-2.31.so libc.so.6 won't work because:
# This will fail:
/bin/ln: error while loading shared libraries: libc.so.6: cannot open shared object file

Since Bash builtins still function, try these methods:
Method 1: Using echo and /proc magic
# Find the actual libc path first (may vary by distro)
$ echo /lib/x86_64-linux-gnu/libc-2.31.so

# Create symlink via procfs
$ echo -ne '#!/bin/sh\nln -sf "$1" "$2"' > /proc/self/fd/1 | sh -s /lib/x86_64-linux-gnu/libc-2.31.so /lib/x86_64-linux-gnu/libc.so.6

Method 2: Direct filesystem manipulation
# For ext4 filesystems (risky but effective)
$ printf 'symlink\t/lib/x86_64-linux-gnu/libc-2.31.so\t/lib/x86_64-linux-gnu/libc.so.6' > /proc/self/fd/1 | debugfs -w /dev/sda1

Method 3: Using LD_PRELOAD trickery
# Create temporary loader
$ echo 'int symlink(const char *t, const char *f) { return 0; }' > sym.c
$ gcc -shared -o sym.so sym.c -fPIC
$ LD_PRELOAD=./sym.so /lib/ld-linux-x86-64.so.2 /bin/ln -s /lib/x86_64-linux-gnu/libc-2.31.so /lib/x86_64-linux-gnu/libc.so.6

To avoid future disasters:

Keep recovery shell binaries statically compiled (busybox)
Maintain backup symlinks in /root
Consider using chattr +i on critical symlinks



Distribution
Typical libc Path


Ubuntu/Debian
/lib/x86_64-linux-gnu/libc-2.31.so


RHEL/CentOS
/lib64/libc-2.17.so


Arch Linux
/usr/lib/libc-2.33.so