Recently I have needed to keep a long running sessions open on a server. And I have been using tmux for this purpose for quite some time. However, my internet connection has been flaky, so I’ve been dropping the connection very frequently. So I wanted to automate the steps. I also had the requirement that the server would have no custom configuration for tmux.
What I came up with was the following command:
ssh -t example.com "tmux attach-session -t chris || tmux new-session -s chris"
The -t option tells ssh to treat the command like a pseudo-terminal, so you can run interactive commands.
The two or’d tmux commands will connect to a new session if it exists, or create a new one if it doesn’t.
When I roll that up into a little bash script that will name the session the name of my user on my local machine:
#!/bin/bash
set -e
server=$1
if [ -z "$1" ] ; then
echo "Usage: $(basename $0) hostname [session name]"
exit 1
fi
name=$2
if [ -z "$2" ] ; then
name=$(whoami)
fi
ssh -t $server "tmux attach-session -t $name || tmux new-session -s $name"