I'm following this guide on how to set up passwordless SSH authentication with ssh-agent.To start up ssh-agent the author recommends the following code in .bash_profile:SSHAGENT=/usr/bin/ssh-agentSSHAGENTARGS=-sif [ -z $SSH_AUTH_SOCK -a -x $SSHAGENT ]; then    eval `$SSHAGENT $SSHAGENTARGS`    trap kill $SSH_AGENT_PID 0fiI don't understand why it is trapping signal 0. According to man 7 signal there is no such signal.Is this just a typo or bug or does this really achieve something?
What is signal 0 in a trap command?
bash;signals;trap
From the bash manual:trap [-lp] [[arg] sigspec ...]... If a sigspec is EXIT (0) the command arg is executed on exit from the shell.