add: fish config file for linux and npiperelay

.config/fish/config-linux.fish

@@ -0,0 +1,6 @@
+#x-server
+set -g DISPLAY $(cat /etc/resolv.conf | grep nameserver | awk '{print $2}'):0
+
+if test -x (command -v npiperelay.exe)
+  source (dirname (status --current-file))/config-npiperelay.fish
+end

.config/fish/config-npiperelay.fish

@@ -0,0 +1,20 @@
+# Configure ssh forwarding
+set -x SSH_AUTH_SOCK $HOME/.ssh/agent.sock
+
+# use square brackets to generate a regex match for the process we want but that doesn't match the grep command running it!
+set ALREADY_RUNNING (ps -aux | grep -q "[n]piperelay.exe -ei -s //./pipe/openssh-ssh-agent"; echo $status)
+
+if [ $ALREADY_RUNNING -ne 0 ]
+    if [ -S $SSH_AUTH_SOCK ]
+        # not expecting the socket to exist as the forwarding command isn't running (http://www.tldp.org/LDP/abs/html/fto.html)
+        # echo "removing previous socket..."
+        rm $SSH_AUTH_SOCK
+    end
+
+    # echo "Starting SSH-Agent relay..."
+    # setsid to force new session to keep running
+    # set socat to listen on $SSH_AUTH_SOCK and forward to npiperelay which then forwards to openssh-ssh-agent on windows
+    begin
+        setsid socat UNIX-LISTEN:$SSH_AUTH_SOCK,fork EXEC:"npiperelay.exe -ei -s //./pipe/openssh-ssh-agent",nofork >/dev/null 2>&1 &
+    end
+end