How to Solve Error - Mesg: Ttyname Failed: Inappropriate Ioctl for Device Error in Linux

1. Cause of the mesg: ttyname failed: Inappropriate ioctl for device Error in Linux
2. Modify User Profile on Linux System
3. Avoid Using the Login Shell Altogether

In this article, we will learn how to resolve the error mesg: ttyname failed: Inappropriate ioctl for device in Linux. We will discuss some reasons causing this error and show how to fix the error.

Let’s begin with what causes this error in a Linux system.

Cause of the mesg: ttyname failed: Inappropriate ioctl for device Error in Linux

In Linux, this error is caused by an interaction between the default vagrant configuration config.ssh.shell to be bash -l. The Vagrant SSH shell command is bash -l.

This prompts the Vagrant’s internal SSH shell communicator. In Linux, the Vagrant runs commands as a root so that it will source this /root/.profile path.

The /root/.profile path contains the mesg n command on the Linux system. This command ensures that no other user can write to your terminal device.

However, there is no terminal device when we run commands on Vagrant. So, the mesg n is not compatible with it, which causes the error.

We can fix this error using one of the following methods in Linux.

Modify User Profile on Linux System

We can resolve this error by modifying the user profile on our Linux operating system. First, we need to open the profile using the following terminal command.

$ /root/.profile

After this, we need to replace the mesg n || true with tty -s && mesg n. This method will work because the mesg -n command is only called if the terminal device is present.

So, when we run the command now, it will run on a non-interactive login shell. Hence, the system will show any error.

Avoid Using the Login Shell Altogether

Another solution to this error is to avoid using the login shell altogether. We change the config.ssh.shell to Bash without the -l flag in the Vagrant setting.

By doing this, the system will not display the error on our Linux system.

We hope you find this article helpful in understanding how to fix the error mesg: ttyname failed: Inappropriate ioctl for device in Linux.