Plan 9 from Bell Labs’s /usr/web/sources/contrib/someone/root/rc/bin/ssh
#!/bin/rc # ssh host arg... - invoke ssh v1. if it fails, try v2. rfork e if (test -w /dev/label) { olab=`{cat /dev/label} label ssh $* } if (! /$cputype/bin/ssh1 $* >[2]/dev/null) exec /$cputype/bin/ssh2 $* if (test -w /dev/label) label $olab