I recently came across an article which tries to address the problem of SSH agent forwarding with screen. Briefly, the problem is that reattaching a screen instance breaks agent forwarding because the required environment variables aren't present in the screen instance. The solution given didn't quite work for me though because I use an SSH wrapper script which automatically runs screen.

My solution is to write a screen wrapper script which stores the environment variables in ~/.sshvars (as export statements) and then starts screen. Running source ~/.sshvars in the shell then makes the variables available. (I created an alias called fixssh to do this.)

I like to put wrapper scripts in ~/bin with the same name. This didn't work out the box however, since ~/bin is only added to PATH in ~/.profile but this file is only sourced if the shell is interactive. The fix is therefore to add the following to ~/.bashrc, but near the top before the [ -z "$PS1" ] && return line.

if [ -d "$HOME/bin" ]; then
    PATH="$HOME/bin:$PATH"
fi