MacOS – How to verify if SSH is disabled with the Terminal on Sierra

EDIT: On Yosemite (OS X 10.10) use this instead:

function ssh () 
{ 
     servername=$(echo $@ | sed -E 's|([- a-zA-Z0-9:/]+)( *[^@ ]*@)([^@ ]*)|\3|')
     echo -ne "\033]0;${servername}\007";
     /usr/bin/ssh $@
}

Note that the function expects username and server name to be specified as user@server (you can use the server IP address too: user@a.b.c.d, the tab name will be set to a.b.c.d). Other combinations like -l user server won't work properly.

You can unset the function with:

unset -f ssh

You can create a function named ssh that sets the terminal tab name and then invokes /usr/sbin/ssh:

function ssh () 
{ 
    servername=$(echo $@ | sed 's|\([- a-zA-Z0-9:/]\+\) *\([^-]\+@\)*\([-a-zA-Z0-9.]\+\)|\3|' | awk '{print $1}');
    echo -ne "\033]0;${servername}\007";
    /usr/bin/ssh $@
}

• servername=$(echo $@ ...

  The first line extracts the server name from the arguments passed to ssh. I tested it against several possible ssh invocations with and without arguments but can't promise it's bullet proof.

• echo -ne "\033]0;${servername}\007";

  The second line is where the magic happens. \033]0;<name>\007 is a ESCAPE sequence that sets the terminal tab name. See this Wikipedia article for more information - this particular escape code is listed in the non-CSI codes section.

• /usr/bin/ssh $@

  Start /usr/bin/ssh with arguments provided.

Add the function to your ~/.bashrc file (if you don't use bash modify it to match your shell syntax and add it to your shell's startup file) so that it's always accessible.

Note that it will also set the terminal tab name when executing a remote command:

ssh user@server command

for example:

ssh jaume@myserver ls -l /

When you want to connect to an unroutable address like link-local you need to specify the interface. This is because for unroutable addresses your system can't determine the outgoing interface by looking at the routing table.

Unroutable destinations include link-local addresses (fe80::) and link-local multicast (ff02::) and more.