Definition of Null It means nothing. “Null and void” In discrete math, null means “null set” which is a set with no values in it. (I think… I’m a little rusty). More on hinative.com

Essentially, the whole command is telling the computer not to take notice of an error and to dump any error messages rather than clutter up the screen or a log file. When you run a unix command, it will either be successful, in which case the output is sent into pipe#1 (which normally points to the monitor screen), or it will fail with an error message which is sent into pipe#2 (which might empty into an error log file or the monitor). The ">" is a command that can redirect those output pipes. In this case it is being told to redirect pipe#2 (the error pipe) to a special unix software device called /dev/null which is basically an infinitely deep hole down which you can throw output that no one cares about seeing. More on reddit.com

It is fine to have null values in data sets. If something can be NULL you are saying, it’s okay to not have it. You just need to make sure that when operating on something that could be null you are checking before operating on it. If(possiblyNullValue) {console.log(“it’s not null”)} More on reddit.com

In IT, it depends on the topic/language. In C, NULL is even defined as 0 - so there's no difference (apart from possible compiler warnings). In C++ for example the builtin keyword "nullptr" exists, therefore you can simply say "Nullpointer". You can use this term in other languages as well if the concept of a pointer exists. In Python, the name is "None", so we use "None" (pronounced the Denglish way "Nan" and yes, to be confused with "not a number"). In SQL, it's usually clear since you need to write "is null" instead of "= 0", so we say "ist Null" und "gleich Null". Whenever there is ambiguity, I try to pronounce "null" the English way, "Nall" would be the closest German. This differs significantly from the German "Null". I was always asking myself: why are there so many zeros in English? Zero, null, nil, oh, love (tennis). Oh, and I forgot about "nought". Anything else?! In IEEE754 floating point arithmetic, we even have +0 and -0, quite funny for non-IT people as well. More on reddit.com