After completing these activities you should be able to:
A shell command consists of a name, zero or more arguments, and zero or more options. For example:
move /-Y C:\Users\billy\Downloads\vacation.jpg photos\archive\vacation.jpg ---- --- ------------------------------------- ---------------------------- \ \ \ \ \ \--- option \--- argument \--- argument \ \--- name
-character in Windows (with a
-character in UNIX), they modify the operation of the given command
mkdir foo barcreates two directories,
bar, while the command
mkdir "foo bar"creates a single directory named
foo bar. Note that this is different from
mkdir "foo bar"which creates a single directory named
.refers to the current working directory,
..refers to the current working directory.
What directory would you suspect the parent directory of the root directory (directory at the top of the file system hierarchy) is, in other words what directory is the parent directory of the root directory? ... The root directory is its own parent directory.Try this:
dir. To move down in the hierarchy from your current drive letter, you type
cdfollowed by the name of the folder you want to move down into (
cdstands for "change directory"). The argument to
cddoesn't need to be a name, it could be a path (starting from the current directory) several directories deep, it could be
., which makes
cdchange to the current working directory (essentially not changing the current directory), it could be
..which makes cd go up a level in the hierarchy rather than down. In fact,
..\..\.., etc. are allowed for going up multiple levels in a single step. Also we have:
mkdir argument1— Makes a new directory named argument1 in the current directory
del argument1— Deletes the file named in the argument.
rmdir argument1— Deletes the directory named in the argument.
copy argument1 argument2— Copies the file named in the first argument, and gives the copy the name provided by the second argument
move argument1 argument2— Moves the file named in the first argument to the name provided by the second argument
type argument1— Prints the bytes of the file argument1 interpreted as ASCII characters to the screen. Don't try this on a non-text file!
.exefile), as well as some bookkeeping information that allows the OS to monitor the process' execution status, resources, and privileges. In fact, more than one instance of the same Program could be executing simultaneously — each instance would be its own separate process.
dir /Qlists directories and files along with their owners' usernames.
m209999was really launched at the behest of the person whose username is
m209999. That means that the login procedure is very important.
The Operating System manages user accounts, logins and process/file permissions. This job is crucially important for security. If user
m209999 is allowed to launch a process and access data whose owner is listed as
... well, we've got trouble. That would give
m209999 access to
The files a user has rights to access is constrained.
Generally, however, there will be one account with unlimited
privileges (so, for example, they can read every file on the
system, regardless of the usual user permission schemes).
A user with these unlimited privileges is called an Administrator (Windows) or
root (UNIX) user, a.k.a. a super-user account. Sometimes, regular users may be able to run a Program
with elevated privileges (we say elevated privileges to
the process/user can do things they ordinarily could not)
using a special password or via special permissions on the Program.
In Windows 10, a User Account Control dialog box opens
up when a program asks to run with elevated privileges.
In UNIX, a shell command is prefaced with
(super-user do) to run that command with elevated privileges.
The ultimate prize in attacking a computer is to be
able to run Programs with super-user privileges, because then
you essentially "own" that machine. In particular, if you can
launch a command shell with elevated privileges, game over ... you win.
A typical use of the LAN is creating and reviewing personnel fitness reports and evaluations, which are subject to privacy protection. Although the operating system provides access control to files, the file owners must specify which users should and should not have access.
The only user that is immune to file permissions is an Administrator (super-user). Because of this immunity, the number of people with Administrator privileges should be kept to a minimum. An Administrator account should only be used, as necessary, to perform system administration tasks, such as system log reviews or user account management.
Depending on the command, any Officer could be placed in charge of the ship's network administrators and, therefore, be given Administrator privileges. With that power comes serious responsibility. Responsibility to use the elevated privilege, as required, to perform system administrative tasks only.