I'm a DOS/Windows programmer with over 20 years experience. I basically taught myself everything by researching what I needed to know. I'm quite willing to do it again (command line stuff doesn't faze me one iota) but I was wandering if there is such a thing as a "command line reference guide" listing commands, what they did and syntax - much the same as the old DOS 5 manual I used all those years ago.

Thanks in advance, and remember, I named myself NFI here for a reason

Do you mean something like this?
http://www.ss64.com/bash/
Google is your friend (I used bash commands)
cheers,
jdk

Hi and welcome to LQ!

You can take a look at the "GNU/Linux Command-Line Tools Summary" where all the common commands are listed divided by category. You will find a lot of useful documentation on the tldp.org site.

To know the exact syntax of a command you have to use the manual pages (the man command). The apropos command can be useful to find commands when you don't know their name.

I've googled my brains out and got nowhere - nothing to get me started at least. As I said I didn't call myself NFI for nothing. For example, bash Vs Sudo what's the dif? any benefits of using one over the other?

Thanks very much for the warm welcome colucix! The link you gave looks like it could be very useful, and I'll be going through it thoroughly ASAP.

See, your last paragraph is an example of what I meant - coming in at below ground level. In all my "googling" I've seen references to "man" but nothing into what it does, and how to use it. Now I have a clue in that area. Never seen "apropos" mentioned before though...

Thanks again for the help.

They are two different things. Bash is a shell, the environment in which you type commands and do things, while sudo is a command. sudo executes a command as another user, commonly the root user. It's usage is very common in Ubuntu linux, where the root is not set up and you need sudo to execute administrative tasks.

You can learn about man just issuing
use "space-bar" to go down by one-page, "b" to go back, "enter" to go down by one-line, type "/word" to search an occurrence of the "word", "n" to search the next occurrence, "q" to quit the manual.

BTW, "q" (quit) to exit man pages ... (I answered this earlier today). "man man" works and will help.
sudo is a command - one command; try "man sudo"

Edit: ... too late ...

This is a very good Linux tutorial: http://rute.2038bug.com/index.html.gz
See also http://linux.die.net/man/