Originally Posted by cedkhader
Do any commands exist in one distro but not in the others?
ARE ALL Distros compatible on the CLI-basis ?
Yes -- a small number.
No -- there are a few small differences: commands that are present on some distros but not on others and commands that behave differently, perhaps in options accepted or format of output.
This is most noticeable on "small" distro's such as BusyBox which are cut back to the essentials.
Distros are Linux (= kernel) plus whatever the distro designers chose to add. Some of the added stuff is very common such as GNU utilities (but even then versions and build details can vary), others -- especially end-user applications -- vary a lot.