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Fix: Wall Not Working Over SSH on Debian

Muhammed T.Muhammed T.·

May 04 2026

·

Linux

On a fresh Debian installation, the wall command (broadcast to all logged-in users) only works on the console... SSH sessions don't receive the message. This breaks the 42 born2beroot project requirement to implement working wall functionality. I couldn't find a solution to this problem using LLMs. Every model I asked either gave generic advice or suggested fixes that didn't work.

Root cause: Missing or incorrectly-permissioned /run/utmp file at boot.

The Fix

Run these commands:

sudo chown root:tty /usr/bin/wall
sudo chmod g+s /usr/bin/wall
sudo bash -c 'echo "f /run/utmp 0664 root utmp -" > /usr/lib/tmpfiles.d/utmp.conf'
sudo systemd-tmpfiles --create /usr/lib/tmpfiles.d/utmp.conf
sudo systemctl restart systemd-logind

Why It Works

  1. chown + chmod — Gives wall binary group permissions to access tty
  2. tmpfiles.d/utmp.conf — Ensures /run/utmp is created with correct permissions (0664 root:utmp) on every boot
  3. systemd-tmpfiles --create — Applies the configuration immediately
  4. systemctl restart systemd-logind — Forces re-read of /run/utmp

Verify It Works

Open two SSH sessions:

Session 1:

wall "test"

Session 2 should receive:

Broadcast message from user@hostname (pts/0) (Mon May  4 10:10:46 2026):
test
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