I'm writing a Graphite/Diamond collector measuring network latency. Specifically it should measure the time it takes to open up a connection to a port on a remote server. And it needs to work via script, i.e. no humans on the keyboard running this interactively.
To give an example with a fictional parameter to telnet which would do exactly what I need.
time telnet --close-connection-immediately-after-established somehost.somedomain.com 1234 Trying somehost.somedomain.com... Connected to somehost.somedomain.com. Escape character is '^]'. Connection closed automatically after established. real 0m3.978s user 0m0.001s sys 0m0.003s
Basically, what's a command-line way to output 3.978 given the example above using only builtin tools?
You could wrap the telnet in an expect script I suppose and have it issue:
... but that seems rather ugly. Any ideas?