How difficult would it be to enhance the client ssh_config file to allow
command-based declarations similar to that provided by the "Host" keyword?

The main reason I need something like this is when ssh is used via CVS and
Subversion. I want all CVS/Subversion traffic to use a different SSH port
and different authentication options.

So... you might have an ssh_config file that contained:

Command '* cvs server' '* svnserve -t'
Port 2200
Protocol 2
BatchMode yes
PasswordAuthentication no
PubkeyAuthentication yes

Where the string matched against the pattern is the complete command line
passed to the ssh client.

This would allow all CVS traffic to use one setting, but normal SSH
traffic to the same host could use different settings.
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