If your machine hits its limit for
ptys, you'll be unable to open another pseudo terminal.
When attempting to open a new terminal, you may run into errors like the one below
[forkpty: Device not configured] [Could not create a new process and open a pseudo-tty.]
You can check what the current limit is by using the following command
$ sysctl -a | grep kern.tty.ptmx_max kern.tty.ptmx_max: 127
To temporarily increase this limit to 255, run the following command
$ sudo sysctl -w kern.tty.ptmx_max=255
This will bump up the limit until the next restart of the machine.
To change this value permanently, create or open the
/etc/sysctl.conf file and add the following line
If you had to create the file, you'll probably want to alter the permissions on it by using the commands below.
$ sudo chown root:wheel /etc/sysctl.conf $ sudo chmod 644 /etc/sysctl.conf