Monday, October 20, 2008

Gotcha Of The Day - screen not starting up - no ptys found

While setting up a new Linux server (hmmm, this seems to be a weekly occurance), my first order of business was to install screen. That way, a lost ssh connection doesn't mean a lost working session.

I installed screen by saying:

sudo yum install screen

I went to run screen and was greeted with the error message No more Ptys. This took a fair amount of Googling to solve. Eventually, I figured out that this was related to some incorrectly created /dev/* files.

The fix boiled down to:

mknod /dev/ptmx c 5 2
chmod 666 /dev/ptmx
mkdir /dev/pts 
chmod 755 /dev/pts

mount -t devpts -o gid=4,mode=620 none /dev/pts

It's also a good idea to confirm your /etc/fstab includes a devpts entry like:

devpts  /dev/pts   devpts  gid=5,mode=620  0 0

Once the problem was solved, I could get back to the fun work of copying over files, creating new databases and generally getting the server humming along.


  1. I'll have to keep this in mind in case I ever run into the same problem. scree is probably my favorite unix utility, especially as a telecommuter.

  2. Yeah, screen is a work of art. It's just awesome.

    I simply wasn't going to work on a server that didn't provide it.