Just basic conventions and terminolgy often used in Debian and Linux.
Note some terms and symbols have different meanings in different contexts. A living language changes over time so legacy (recent history) terms may have different meanings to different people, please add yours. These are only based on what I have come across and understood so I may have been completely wrong, as always corrections and additions most welcome this is a book (community) page so just hit the edit tab and leave a comment on what you fixed.
meaning some program. Like 'x' in math a place holder used to make a statement generic. So "gksu foo" could mean "gksu Konqueror" or "gksu Nautilus".
friend of foo (see above) sometimes used together "foo bar" or "foobar" again as in math but a different variable place holder like 'y'.
1)the administrative user that has all power to do things on a linux/unix computer.
2)"/" is the root symbol, pronounced root, and often meaning the begining (or base point) of a *nix file system.
meaning all things ending in "nix" mostly referring to "Linux" "unix" (or "bsd" variants?)
abbreviation of "application" or program sometimes referred to as clients.
read the man page
means open your favourite terminal application (xterm, konsole, linux console etc) and then type:
see foo above, in this case it is the name of the app that you are trying to use so try:
$ man ls
Most *nix programs have this very handy manual page installed along with the program. They are your friend and should always be consulted BEFORE you run any unfamiliar command, that includes help given here and elsewhere. A small typo by the helper could cause you to make a big mistake so check what all those options do and you will learn more.
KDE programs often do not have a man page, they have their own help system, a rare KDE failing IMO. How about gnome and other desktops?
means open your favourite terminal application (xterm, konsole, linux console etc) and then type "mount" and press enter (return key). The "$" normally appears as the prompt when logged in as a normal user.
run ifconfig, as root:
means open your favourite terminal application (xterm, konsole, linux console etc) and login or gain root. Then type "ifconfig" and press enter (return key). The "#" normally appears as the prompt when logged in as the root user.
login as the root user or run the program with root permissions. Most often done by opening your favourite terminal application (xterm, konsole, linux console etc) and typing "su" pressing enter (return key) and entering the requested root password. May also be accomplished by dropping to the Linux console and logging in as the root user (press "Ctrl+Alt+F1" if in X, "Alt+F7" gets you back to X). Or by using kdesu, gksu or xsu to run the program as the root user.