Run commands on remote machine with ssh

Running a simple command on a remote machine with ssh is straight forward:

ssh workhorse 'echo $HOSTNAME'

However, watch out for shell expansion on the local machine (i.e. use either 'echo $HOSTNAME' or "echo \$HOSTNAME").

This is useful, amongst other things, in makefiles where a target can be created by executing a batch file on a remote machine as long as it’s ssh accessible. For example, given the following makefile

foo.batch:
    @echo "echo \$$HOSTNAME" > $@
    @echo "pwd" >> $@
run: foo.batch
    ssh workhorse 'cd $(CURDIR) && bash $<'

make run on some machine with ssh access to workhorse will execute foo.batch on workhorse and the target will wait for execution to finish.

The output should be

workhorse.somedomain.com
/path/to/pwd

Remember that this works best if the connection can be made without the need to enter a password, for example using a key pair or kerberos ticket.