Why do different environments contain different command line options when calling man ls?
Does it mean that I should just use man command with options before using the bash options for each new environment which I use?
There's nothing magical about ls - it's a program just like any other program. Specifically, one that' been around for a long time. as such, different environments may have slightly different versions or even different forks of it. It's usually safe to assume the common options (such as -l) would be available anywhere, but when in doubt - you should double check.
