Regarding opening snacks like Bamba and potato chips (nylon bags that are glued shut on the top and the bottom) in the regular way on Shabbos, many people do this, but I not able to find a sefer that says explicitly that this is OK. I only find seforim that say it is not OK to open these bags on Shabbos.
Can you clarify this issue?
It is true that most poskim say that it should not be opened in the regular way of ripping it where it is glued together. This is because according to the Sulchan Aruch Horav, and Chayei Adom (NIshams Adom 29-2) it is considered koreyah to rip something in the place that it was glued. it is ripping and mileches korayah, it can also be boneh, and making a kli. See Hilchos Shabbos B’shabbos 14-39, Orchos Shabbos 12-23, Knei Bosem 1-22, Shmiras Shabbos Khilchoso chap. 9 ftnt. 21, The Shabbos Home pg. 87. Also see Igros Moshe O:CH 1-122(10), that even though it technically may be permitted to open, but it should still preferably be opened before shabbos because it is easy to make mistakes with these things. Also see Nishmas Shabbos 7- 265, that says that it is preferable not to open them this way, but someone who opens up a small bag in this manner has who to rely on, but again this is not according to most poskim, who say that they should be opened wither in a way that ruins the package or at least not by the glued part.