A bug is a mistake in the design or source code of a computer program that causes it to behave in an undesirable and unintended way. Occasionally a bug in a compiler will cause a bug in a program compiled using it. Bugs are virtually impossible to eliminate from non-trivial software. Thus it should come as no surprise that NetHack has its share of bugs.
A user has suggested improving this page or section as follows:
"More discussion is needed regarding the general nature of bugs and general comment re. bugs in nethack, including bug reporting/fixing process. Discussion of individual bugs should go on an individual page for that bug."