I mean, when I place a shortened link in my online portfolio to a site which I built, will my client be able to see that I linked to him from my portfolio site? (via his stats or analytics). He saw my direct link, so now I want to sort-of hide my portfolio link behind shortnened url. Will that work?
From bit.ly: https://bitly.com/a/help#i_3_5
Why don't my bitly links show up in my server logs?
bitly uses 301 permanent redirects. That means that the referring site is passed through to your server transparently, which is why you don't see bitly in your logs. This is by design, as it preserves the genuine referring sites, as well as the original page rank.
You'd have to check the docs of other url shorteners, or operate your own (http://yourls.org/).