I expect all military who fight in wars know how to use guns. Do all inductees know how to shoot or do they train them to shoot to kill?

Boot camp.  Of course we train them. 

In the Navy we were not trained in weaponry in boot camp. Many of us learned and qualified when we got to our next command, depending on our job. My post at a security point required me to be proficient with .45 caliber pistol and a 12 guage shotgun. We were also required to qualify each year with shooting, disassembling and reassembling a M-14 rifle. Many sailors never carried or used a weapon.

Most armies the world over train soldiers pretty much the same basics, and those include how to use and look after guns properly, and shoot accurately. In action it's very often you kill your enemy before he kills you or your mess-mate.

Nasty, but I have a heard a general admit I think in a radio interview that war is cold-blooded mass-murder.

Notably the armed services try to avoid the personal element. The infantry see other. Blow up a tank though, and you've wrecked an armoured tractor carrying a big gun, not killed the 3 or 4 men in it. Sink a ship or submarine and you've removed something that can sink yours, not drowned several hundred men - navies tend at least try to rescue the survivors if they can safely do so. (Though no-one will survive from a submarine torpedoed in the ocean.)