The overall role of Linux is to provide a Unix like Posix compliant kernel that when used in conjunction with other software and packaged into a "distribution" (eg. Debian, Gnewsense, Ubuntu) provides a complete operating system environment that can be used on a variety of different processors.
In other words, a GNU/Linux distribution allows the user to do everything you would expect an Operating System to do, as well as provide all the applications that a user would need to use to accomplish tasks on a computer (eg. web browsing, email, word processing, spreadsheet calculations, database formulation, archiving etc.)
Because Linux and the majority of the other software found in most distributions is licensed under the GNU Public License, a user can expect to have the freedom to do the following:
This is in stark contrast to most proprietary software which generally restricts your usage of that product to usage deemed acceptable to the owner of the software (ie the software company) through End User License Agreements, most of the terms of which most users do not read and do not understand.
No. Linux, like Unix, is designed to be a multi-user system.
crontab -e
The last answer to this was incorrect. Whether or not you are the only user on the system or not: Linux is always a multi-user operating system.
ifconfig
The Linux administrator is called the "root" user.
With most Unix-derived systems, "root" is the super-user account.
Yes, as long as they have user accounts on both machines.
No. There is no single user interface for Linux. GNOME. KDE, Xfce, Fluxbox, and CDE are all examples of user interfaces / desktop environments for Linux.
There is no singular user interface for Linux. Linux itself makes no requirement for a user interface. There are plenty of interfaces: GNOME, KDE, Xfce, LXDE, BASH, ZSH, CSH, TSH, FISH, and dozens of window managers.
multi-user system
A Linux user can belong to multiple groups, and in most circumstances, it would be very difficult to utilize a Linux system without being so.
unix and linux systems are true multi user (root + others) but in windows admin and main user are same !