The cable came out on my left hand shifter (the friction one), and now it won't stay back in. There's a small black plastic collar where it enters the housing that has broken off, but I can't believe it was only being held by that little thing! Yet I've taken the shifter apart, and the cable does not appear to be designed to go all the way into the housing, because while the hole on the outside can take the circumference of the black cable housing, on the inside, this hole is only large enough for the derailleur cable to pass through - not all of it. So not sure what's the cable housing is supposed to be held by. This probably happened as a result of my raising the handlebars, and not paying attention to the extra tension this created on the shifter cable, when I used the shifter. By using it this way, the cable sliced through the housing, a few inches long.
The shifters are Suntour Wishbone friction/index shifters. I'd hate to have to replace them at this point, so I'd like to know if I can repair this by simply buying new cable housing. I am doubtful, because it seems to be non-standard. It appears the shifter cable (going to front derailleur) was inside a white plastic covering, and is surrounded by a number of steel cables, and all of this is housed in the black cable housing.
(First pic shows the black cable housing held by plastic ties, the interior white plastic housing, the derailleur cable entering the shifter box, and stranded steel cables inside the black cable housing. Third pic shows a better view of the hole in the shifter box and the stranded steel cables. Second pic shows what the thing is supposed to look like intact!).