

But at the core is gdb and - usually - there is a window somewhere that you can stuff gdb commands into. Of course, if you use an IDE, it very likely is a front end for gdb among other things. In fact, gdb has two potentially built-in interfaces although depending on how you install gdb, you might not have both of them. Of course, not everyone’s a fan of gdb’s text-based interface, so there’s no shortage of front ends available for it.

There is lldb and a handful of non-open commercial offerings, but for the most part you will use gdb to debug software on Linux. If you are looking for a Linux debugger, there are only a few choices, but gdb is certainly the one you will find most often. The harder something is to create, the less likely there is to be many of them. If you want to use the Large Hadron Collider, you have a choice of exactly one. If you want to buy a jetliner, there are fewer choices. If you want to buy a car, there are plenty of choices.
