Remove need/use of password.txt (EleutherAI#795)

Removes redundant generation/use/deletion of password.txt by placing the password as a variable and running echo with the variable directly.

Previously, the text 'password' was echoed into password.txt, then read from it again, before the file would finally get deleted.

Dockerfile

@@ -31,19 +31,17 @@ RUN apt-get update -y && \
 
 ### SSH
 # Set password
-RUN echo 'password' >> password.txt && \
-  mkdir /var/run/sshd && \
- echo "root:`cat password.txt`" | chpasswd && \
+ENV PASSWORD=password
+RUN mkdir /var/run/sshd && \
+ echo "root:${PASSWORD}" | chpasswd && \
  # Allow root login with password
  sed -i 's/PermitRootLogin without-password/PermitRootLogin yes/' /etc/ssh/sshd_config && \
  # Prevent user being kicked off after login
  sed -i 's@session\s*required\s*pam_loginuid.so@session optional pam_loginuid.so@g' /etc/pam.d/sshd && \
  echo 'AuthorizedKeysFile .ssh/authorized_keys' >> /etc/ssh/sshd_config && \
  echo 'PasswordAuthentication yes' >> /etc/ssh/sshd_config && \
  # FIX SUDO BUG: https://github.com/sudo-project/sudo/issues/42
- echo "Set disable_coredump false" >> /etc/sudo.conf && \
- # Clean up
- rm password.txt
+ echo "Set disable_coredump false" >> /etc/sudo.conf
 
 # Expose SSH port
 EXPOSE 22