Basic commands for working with ms dos. Commands for working in MS DOS environment

The newly created subdirectory can be filled with files. A file representing a directory takes up 4 KB of memory on external media, so creating new directories is not a harmless operation in terms of memory consumption on external media.

Command specification: RD [n:]route / RMDIR [n:]route

The directory must be empty. The current and root directories cannot be deleted.

Removing a subdirectory is done with the RD command. As long as at least one file is registered in the subdirectory, it cannot be deleted. Even if you try to do this, the system will not complete this operation. Deletion can be done in any directory.

Example:

C:\WORK>rd pro

C:\DOC>rd\work\pro

The first command removes the PRO subdirectory from the current WORK directory. The second command deletes the same subdirectory, although the current one is the DOC directory.

Command specification: PATH [[n:]route[[;[n:]route]...]]

If the executable file is not found in the current directory, then it is searched sequentially in the directories listed in PATH, without changing the current directory. The PATH command without parameters returns the current list of alternative routes. PATH command with parameter ";" cancels previously established routes. The PATH command does not make any changes to the file system or to the current directory setting.

The standard argument to the PATH command contains the designations of one or more routes, separated by a ";".

Example:

C:\>path c:\;c:\exe

This command means that files not found in the current directory should be searched first along the route C:\, then along the route C:\EXE.

The PATH command usually appears in the "autoload" command file - AUTOEXEC.BAT. Therefore, the end user usually does not notice that this command has actually worked. But he can always find out which alternative routes are currently installed. To do this, simply issue the PATH command without arguments.

You can cancel installed alternative routes with the command:

– integers) moving the Draftsman from a point with coordinates (x, y) to a point with coordinates (x + a, y + b). If the numbers a, b are positive, the value of the corresponding coordinate increases, if they are negative, it decreases.
For example, if the Draftsman is at a point with coordinates (2,3), then the Move to (-5, 2) command will move the Draftsman to the point (-3,5).
Record
Repeat k times
Team1 Team2 Team3
end
means that the sequence of commands Command1 Command2 Command3 will be repeated k times.
The draftsman was given the following algorithm to execute:
Repeat 3 times
Shift by (-1,-5) Shift by (-2, -2) Shift by (4, 1)
end
What command must the Draftsman execute in order to return to the starting point from which he started moving? Answer:

Move by (–3, –6)
Move by (-3, 6)
Move by (-1, 2)
Move by (1, -2)

leading to...”2. The structure of an algorithm, all commands of which are executed in turn only once, is called: a) Linear. b) Branching. c) Cyclic. d) Recursive. 3. The property of an algorithm to contain only those commands that are understandable to the performer is called: a) determinism; b) mass character; c) understandability; d) unambiguity.4. What is the name of the property of an algorithm that reflects a clear separation of steps and their sequential execution: a) unambiguity; b) effectiveness; c) understandability; d) discreteness.5. What is the name of an algorithmic design in which, depending on the conditions, either one or another action can be performed? a) Linear. b) Branching. c) Cyclic. d) Recursive.6. Performer The turtle moves on the computer screen, leaving a trace in the vision. At each specific moment, the position of the performer and the direction of his movement are known. The performer has two commands: Forward n, where n is an integer, causing the turtle to move n steps in the direction of movement. Right m, where m is an integer, causing a change in the direction of movement by m degrees clockwise. Record Repeat 4 [Command 1 Command 2] means that the sequence of commands in square brackets will be repeated 4 times. The turtle was given the following algorithm to execute: Repeat 4 [Forward 10 Right 120] What figure will appear on the screen? 1) open broken line c) square 2) regular triangle d) regular pentagon Note : The sum of the exterior angles of a regular n-gon is 360 degrees.7. Determine the value of variable a after executing the algorithm.a:=6b:=22-3*aa:=b/2*aThe order of actions corresponds to the rules of arithmetic. Please indicate only one number in your answer.8. Determine the value of the variable b after executing the algorithm, written in the form of a block diagram: Note: the sign:= indicates the assignment operation. In your answer, indicate one number - the value of variable b.9. The Calculator performer has two teams, which are assigned numbers: 1. add 22. multiply by 3. The first of them increases the number on the screen by 2, the second - triples it. Write down the order of commands in the algorithm for obtaining the number 31 from number 1, containing no more than 5 commands, indicating only the command numbers (for example, 22211).10. Some algorithm obtains a new chain from one chain of characters as follows. First, the original chain of characters is written, after it the letter that is in the first place in the original chain is written, then the original chain of characters is written in reverse order. The resulting chain is the result of the algorithm. For example, if the original chain of characters was LES, then the result of the algorithm will be the chain LESLSEL. Given a chain of characters of the memory. What chain of characters will be obtained if the algorithm is applied to this chain twice (that is, the algorithm is applied to this chain, and then, as a result of its work, the algorithm is applied again)?11. On an endless field there is an endless wall. The robot (P) is above the wall and looking to the right. Write an algorithm that will move the Robot to the first cell by the subwall (k.s.).Rk.s Note: Find out the commands that the Robot can perform from your teacher.

moves along a plane; when lowered, it leaves a trace in the form of a line. The executor can execute commands:
1) move to point (a, b), moving the Draftsman from a point with coordinates (x, y) to a point with coordinates (a, b);
2) shift by vector (a, b), moving the Draftsman from a point with coordinates (x, y) to a point with coordinates (x+a, y+b).
To repeat k times a certain sequence of commands, use the following notation:
nc time
team1 team2 team3
kts
a) Determine what will be drawn after the Draftsman completes the program:

Raise the pen
move to point (3, 1)
lower the pen
move by vector (2, 0)
move by vector (1,1)
move by vector (-4, 0)
move to point (3,1)
raise the pen
move by vector (1,1)
lower the pen
move by vector (0, 3)
move by vector (1, -2)
move by vector (-1, -1)

The field size is 8x8, rows are numbered, columns are designated by letters.
An ant can execute movement commands:
up N,
down N,
right N,
left N, (where N is an integer from 1 to 7), moving the performer to N
cells up, down, right or left, respectively.

repeat k times
team1 team2 team3
kts
means that the sequence of commands command1 command2 command3 will be repeated k times.

If an Ant encounters a cube on its way, it moves it along the way.

For example, let the cube be in a cell B6.
If the Ant follows the commands right 1 down 3, then he himself will end up in a cage B5, and the cube is in the cage B4.

(trace in attachment)

Let the Ant and the cube be positioned as shown in the picture. The ant was given the following algorithm to execute:

repeat 4 times

down 2 right 1 up 2

In which cell will the cube end up after executing this algorithm?

(With detailed solution!)

called the branching algorithm, its function words and block diagram paragraph 3.4 6. What is called the repetition command?

Creates a directory. The MKDIR or MD command can be used to create a multi-level directory structure.

MKDIR [drive:]route MD [drive:]route

The "drive:" parameter specifies the drive on which you want to create the directory. "Route" specifies the name and location of the new directory. The maximum length of one route from the root directory to the new directory is 63 characters (including \).

Deleting a directory is described in the RMDIR command description, and changing it is described in the CHDIR command description.

Let's say you want to create a new directory on the current disk and store income information in it. To create a directory named INCOME, type mkdir \income.

MODE command

Configures system devices. The MODE command performs many different tasks, such as displaying system status information, changing system settings, or configuring ports and devices. This uses different command syntax. The variations of the MODE command are described in more detail below.

Some tasks (such as setting the output mode) can only be performed by the MODE command if the DEVICE command for the ANSI.SYS driver is included in the CONFIG.SYS file. To use MODE to switch the character set, DISPLAY.SYS must be installed.

Although the MODE command can be issued in response to a command prompt, it is useful to include some such commands in the AUTOEXEC.BAT file. This will automatically configure your system when you start your computer.

MORE Team

Displays one screen of data at a time. MORE reads standard input from a pipeline or redirected file and outputs one screen of information at a time. Typically used to view long files.

MORE< [диск:][маршрут]имя_файла имя_команды | MORE

The [drive:][route]filename parameter specifies the location and name of the file with the data being viewed on the screen. The "command_name" parameter specifies the command that transmits the data being viewed on the screen.

When using the redirection symbol (<) нужно задать в качестве источника имя файла. При указании конвейеризации (|) вы можете использовать такие команды как DIR, SORT и TYPE. (Перед этим установите в AUTOEXEC.BAT переменную TEMP.)

Let's say you want to display a long file called NEWW.DOC. To pass this output through the MORE command, give the command more< news.doc или type news.doc | more. MORE выводит первый экран информации и сообщение.

In relation to DOS, all commands are divided into internal (those processed by the command.com command processor) and external, which are system utilities. Thus, the full version of MS-DOS comes with a large number of additional utilities that can be considered as commands. The command line included with Windows only supports internal commands and basic external commands that are necessary only to provide basic functionality and the ability to run programs created for DOS. In addition, a number of commands, strictly speaking, are not DOS commands at all, but are Windows XP console programs.

VER

The VER command (from VERsion - version) is internal and displays the version of the operating system used. For Windows XP it will display the following information:

Microsoft Windows XP [Version 5.1.2600]

And for Windows 7:

Microsoft Windows

So now we know that in fact, Windows 7 is not 7 at all, but 6.1.

DIR

In order to find out what is in the current directory on the disk, use the DIR command (from DIRectory - directory). At the same time, in order to change the current disk, use a command consisting only of the disk name, that is, a letter and a colon (remember to press Enter to execute the commands). So, with the command A: you will go to drive A:. For example, if you insert a new floppy disk into the drive and type first A: and then DIR, you will see something like this:

The volume in device A does not have a label.

Volume serial number: 234F-18F9 Contents of folder A:\ File not found

If there were files and/or directories on the floppy disk, the DIR command would list them, indicating their size and creation date. If there are a lot of files, then you can use the special key w:

In this case, information about the files will be displayed in a compact form - in several columns and without additional information (that is, only names).

CD

In order to change the current directory, use the CD command (from Change Directory - change directory). In this case, the directory is changed according to the “from the current” principle. Let's say you have a directory DIR1 on your C: drive, which contains a directory DIR2. If you are in the root directory of the C: drive (that is, C:\), then to get to the DIR2 directory, you need to enter two DIR commands in sequence:

After this, the system prompt will change to c:\DIR1\>

The system prompt will now change to c:\DIR1\DIR2\>

To move to several directories at once in the file system hierarchy, you need to list them all. In our case, in order not to enter the command twice, we should write:

Cd dir1\dir2

If you need to go to a higher level (for example, from DIR2 to DIR1), you should put two dots instead of the directory name:

M.D.

The MD command (from Make Directory - create a directory) is intended for creating directories. If you want to create a directory "MYDIR" directly inside the current one, then enter:

MD MYDIR

If you are, for example, in the root directory of drive D:, and you need to create a new directory inside another (for example, DIR1 on drive C:), then you need to specify the full path:

Md c:\DIR1\MYDIR

It should be remembered that when executing all commands, DOS starts from the current directory, that is, from the one that you see in the system prompt. And if you need to perform an action in another location, then you must either specify the full path, including the drive name, or change to the desired directory using the CD command.

To copy files, use the COPY command. For example, to use it to copy the file command.com from drive C: to drive D:, you should write:

Copy c:\command.com d:

So here the first parameter specifies the original file name and the second parameter specifies the location of the copy to be created. In the example above, the command.com file will appear in the root directory of the D: drive. If you also need to change the file name when copying, you must also specify a new name:

Copy myfile1.txt myfile2.txt

This copies the file myfile1.txt from the current directory to the file myfile2.txt, which will be located in the same directory as myfile1.txt.

MOVE

If you do not want to copy a file, but move it to a new location, use the MOVE command:

Move myfile1.txt a:\

Thus, the file myfile1.txt from the current directory will be moved to the root directory of the A: drive. If the command is executed successfully, the file will be copied to a new location and deleted in the original location.

DEL

To delete files, use the DEL command (from DELete - delete). For example, if you enter:

Del c:\dir1\myfile1.txt

then the file myfile1.txt will be deleted from the DIR1 directory on the C: drive. If you specify not a file name, but only a directory name, then all files from the specified directory will be deleted.

EDIT

When it becomes necessary to make any changes to a text file, you can use the external EDIT command, which loads a simple text editor included with any version of DOS and Windows 9x. There are two ways to use this program. First, you can simply type "edit" on the command line and press Enter, which will load the editor with a blank document. But it is more advisable to immediately indicate the name of the file being edited, for example:

Edit c:\autoexec.bat

As a result of executing such a command, the AUTOEXEC.BAT file will be loaded into the editor immediately from the C: drive. If you still have Windows 9x installed, you will see something similar to what is shown in Fig. 6.1.

Rice. 6.1. Staff editor with loaded AUTOEXEC.BAT file

On the top line you see the editor menu. The most important is the File menu, with which you can save the edited document (by selecting the appropriate item from it), and also exit the program. In order to switch from the actual area where you can edit text to the menu, press the Alt key and then move between items using the arrows. Looking ahead, I want to note that using Alt you can go to the menu in any Windows program. It should also be noted that in the Windows NT family (including XP, Vista and Seven) this command is not present.

FORMAT

The internal commands discussed above are used to work with files - copying, moving, etc. There are special external commands for working with disk. The FORMAT command is one of the most important and is used to logically format disks.

NOTE
Before the operating system can work with the disk, it must be formatted. When formatting, each physical block of information on a disk is associated with the logical structure of the file system. Please note that once a hard drive is formatted, it is impossible to restore any information previously located on it.

To use this command, you must specify a drive name. For example, to format a floppy disk, you would enter:

Format a:

The FORMAT command has a number of options, the main ones are listed in the table below.

To use a key, enter a command into the command line, then a required parameter (disk name), and then, separated by a space, the name of the key or keys. So, to format a standard 3.5-inch floppy disk, you can enter:

Format a: /f:1.44 /u

You should be extremely careful when using the FORMAT command!

SYS

If you need to create a system disk, you should not just copy the io.sys, msdos.sys and command.com files, but use the SYS command. The fact is that the mere presence of system files does not make the disk a system one - it is necessary for the computer to know where exactly these files are located (and physically, since at the time of boot the OS file system itself is not yet loaded). It is the SYS command that places system files where the computer will look for them to boot the operating system. For example, to move system files from drive A: to drive C:, you would enter:

Sys a:c:

This command is only available in DOS and Windows 9x.

FDISK

The FORMAT command performs logical formatting. In addition, there is also the possibility of logical separation of hard drives. This is done using the FDISK command, to run which you just need to enter its name into the command line and press Enter.

ATTENTION
The FDISK command is only available in DOS and Windows 9x. In Windows XP, creating disk partitions is possible either during the system installation process or using a special Computer Management snap-in. Here we consider the option of preparing a disk in a DOS environment.

When running FDISK, the command will ask whether to enable support for large disks. If you answer “Y” (for yes), then in the future you will work with the FAT32 system. In this case, it becomes possible to create logical partitions with a capacity of over 2 GB. In addition, FAT32 distributes space between files more efficiently than VFAT. After you answer the question about supporting large disks, you will see the main menu of the FDISK program, shown in Fig. 6.2.

Rice. 6.2.

To select an action in this program, press the number corresponding to the menu number, and then press Enter. Return to the previous menu and exit the program using the cancel key (Esc).

CONVERT

This command, on the contrary, is no longer related to DOS and is available only in Windows 2000/XP and higher. With its help you can convert logical drives from FAT to NTFS. To launch it, call the Windows command line (Start "Programs" Accessories). Similar to the FORMAT command, to execute CONVERT you must specify the name of the disk to convert and optionally the destination file system using the FS key:

Convert C: /FS:NTFS

Please note that a disk converted to NTFS is invisible to DOS. In other words, if you boot from a system floppy disk containing DOS (Windows 9x), you will not be able to access NTFS disks.