"Manual pages on the web" requires a caveat

[fthommen]

In 02-filedir the course participants are referred to manual pages on the web using the search terms unix man page. IMHO a strong caveat should be added to this suggestion: Man pages on the web could refer to a (slightly) different version of the command than then one that the user is actually looking for. This version might support different options or - even worse - the same option with a different functionality. It should be made clear to the participants, that "unix" and "linux" are not the same and that even different Linux distributions provide different and sometimes customized versions of the same command. Manpage information from the web (as other information from the web, too) should always be read with a pinch of salt.

[colinmorris]

Related to the behemoth of an issue, #798