I really didn't know about this command ... is it that bad to give me -1? ... I will never ask again here because of this and in the same time thank you you to the guys that actually lost some time to explain.
I'd like to strongly encourage you in the opposite direction, to always ask questions. Always do this, regardless of how others react.
Many younger people have security issues explaining their knowledge with others, and sometimes exhibit this as criticism and acidity. It's possible that's what happened here.
It's also possible that someone disliked your use of the phrase "two words", maybe because they interpreted it literally. Some things resist explanations that are both short and accurate.
Regarding od, it's a flexible format conversion tool that lets you convert arbitrary data to hexadecimal, octal and C escaped printable text. I use it a lot!
I applaud the way you approached it - figuring out every single thing about a tool.
Also, I didn't know about 'od' command. Thanks again!