A lot of ancient roman paintings and greek paintings portrait men with very well cut hairstyles... as also men with no facial hair at all. i was wondering how did they managed to do this? what instruments and objects did they used to accomplish this? ... because only using knives doesn't seem like it would do the work

Examples: http://static3.wikia.nocookie.net/__cb20131201120661/althistory/images/8/8f/Julius_Caesar_Bust.jpg

https://upload.wikimedia.org/wikipedia/commons/f/f5/Diver_Paestum_02.JPG