And another point - any distributions you've received from LINE will be taxed as ordinary income when you sell while any loss will be limited to the difference between your original purchase price and sale price. Be sure to dispose of your entire interest in the MLP in order to apply any carryforward losses. Also, LINE may be passing through large Capital Gains to unitholders depending on how they treat their asset sales. However, you'll be getting those whether you sell or hold so that may not matter but it could up mess up your tax planning.
Tracking cumulative reported operating losses that haven't been deducted, by each individual MLP, is important for offsetting them against distributions that would otherwise be ordinary income. Since MLP operating losses can only be offset aginst income from that same MLP, this task is important. And selling 100% of the position is the only way to get the loss carryover in play.
To date, LINE looks to have about $1.50/unit of capital gains to pass through (assuming book and tax accounting is the same -- never a sure thing). Selling before the close of the latest sale should keep any gain on that transaction from being passed through. Of course, if oyu are like so many others, you are selling LINE at a capital loss and the capital gain pass through can be offset against capital losses.
Actually carryforward losses offset large negative basis adjustments caused by negative earnings. Earnings usually increase basis but when they're negative, they decrease basis. Example - you pay $25 for an MLP who pays $2 per year in distributions and has a $2 per share loss for 2 years. If you sell at the end of year 2, your basis is $17. The $4 resulting from carryforward losses goes on Sched E and offsets a like amount of ordinary income (wages, interest, distributions, etc) so its a wash (assuming you sell your entire interest)