Useful DOS Commands

Introduction:Many course material on the Teaching Network may still use the command line operating system called DOS (Disk Operating System). This requires the user to type specific commands at a prompt. You may also need to use this system, for example, when changing your password, and you can enter DOS by choosing 'MS-DOS Prompt' from the Public menu on the taskbar.
Command Format: Commands can be typed in response to the network DOS prompt:G:\>Commands may be typed in upper or lower case. Here, they are specified in upper case to distinguish them from other input. Commands have a particular format.Some can be usedsimply by typing the command name only, as in:DIRwhich displays a listing of files in the current directory.
Parameters: Many commands can take extra information called parameters to make them more specific, For example, the  COPY command can have a parameter specifying a file to be  copied and a parameter specifying a file to which the copy is to be made. So the command would look like this:COPY filea fileb
In this case, filea would be the name of a file to copy from and fileb would be the name of a file to copy to. Parameters can sometimes be omitted in which case a defaultaction will apply.
Options: Commands can also be qualified by the use of options. Options are preceded by a / sign. A simple example of the use of an option is with the DIRcommand. DIR can be qualified by /P or /W. Thus the commands:DIRDIR  /W DIR  /Presult in listings presented in a different format as detailed later.
Some Useful DOS Commands:COPY --  Make a copy of a file or merge files together.
COPY original-file destination-file
where original-file  and destination-file  are file names, separated by a space.
The command can be used to merge several files into one file since theoriginal-file parameter can be a list of  filenames separated by the + symbol. For example:
COPY file1  + file2 file3would copy file1 and file2 into file3.Note that the file names used in the copy command must
include the file extension if it exists. So if you were copying a fortran program calledfirst.for, for example, you wouldneed to include the .for extension in the filename.
DEL -- Delete a file.
DEL filename
where filename  is the name of the file to be deleted. You are  asked to confirm that you really want to delete the file. Note that the name must include the file extension. The amount of space on a disk is limited and it is necessary periodically to tidy up unwanted files. It is possible to use a '*' character in a filename to match any sequence of characters.This feature is   very useful when deleting unwanted files with identical extensions. For example, when developing programs,DEL  *.objwill delete every binary (.obj) file in the current directory.
Since an  .obj  file can always be recreated from the original source program, it is usually unnecessary to keep it.
DIR: Obtain a list of the files stored in a directory. If used without options this command will give a list of files in the current directory, including any extension (e.g. .for), and their size. If used with the option /P, that is:DIR  /PThe same information will be displayed page by page with the message:strike a key when readyat the end of each page.If it is used with the /W option, i.e.DIR  /Wthe listing is of names and extensions only and in a more compact format across the page.
DISKCOPY: Take a security copy of your working disk. It is very important to have a second copy of your programs and data in case you lose your disk or it becomes unreadable for some reason. Use the DISKCOPY command as follows:DISKCOPY A: A:where A: denotes the drive the disks will be loaded into. When  a copy of your disk is generated in the computer's memory, the computer tells you to remove the first or source disk and insert the disk, which is to become the copy (the target disk).
Insert the target disk and press ENTER. If the second disk is  not formatted it will be formatted automatically. The source disk should be write protected using the tab in the corner in case you mistake it for the target disk (see the chapter on using disks).
LIST:Obtain a printed listing of a file. LIST filename where filename is the file to be printed. If the printer is busy, or if you don't need a printed copy, you can use theTYPE command to view a file on the screen. You could also use an editor such as DOS Edit to display a file, in which case, as a bonus, you would then be in a position to correct any errors you might notice. Remember that the file name must include the file extension. So if you want to print  your Pascal program called first you would need to use:LIST first.pas
RENAME:Change the name of a file. This command can be abbreviated to REN:REN oldname newname
where oldname is the file to be renamed andnewname is the name it is to be given. Note that files on drives other than the current drive can be referred to by prefixing the filename by the relevant drive letter, for example:A:\filename
where the \ refers to the ‘root’ directory of the driveFilenames can also include directories separated by the \ character as in:A:\dir1\dir2\filename
TYPE:View a file on the screen. TYPE filename where filename is the name of the file to be displayed on the monitor screen. If you are looking at a long file, you will need  to press the PAUSE key to stop continuous scrolling. Press the  space bar to continue scrolling when you have read the screen.
FORMAT:To format a floppy disk, place the disk in the floppy drive and type FORMAT A:Note that by default the disk will be formatted to hold about 1.44megabytes of data.Warning: formatting will destroy any data on the disk so onlydo this once!
DOS Command Listing:In the following section, alternative options are separated by the ‘!’ character. Arguments are optional unless in italics. ‘cwd’ stands for ‘Current Working Directory’.

DOS Conventions:DOS commands are not case sensitive. Some commands have switches; these must be preceded by a forward slash (/). Pathnames may be precedd by a drive letter as in ‘X:pathname’ and if no drive or pathname is given the current
directory is assumed.
The Commands:ATTRIB +!-r +!-a pathnameDisplay, or set!clear Read-only or
Archive attribute
BREAK on!off
display, or turn on!off increased level of ^C detection
CHDIR (CD) path
display, or change working directory
CHKDSK pathname   (A: drive only)
check disk or file logical structure
/f          - fixproblems encountered
/v         - verbose; displays filespecs
CLS - clear screen

COMMAND path cttydev
run nested CLI from path with I/O device cttydev
/e:#              - set environment size #
/p                     - do not invoke another CLI
/c command - run command and then enter
COPY pathname   pathname
or
COPY pathname + pathname 
                                copy or concatenate files
/v         - verify writes
/a!b      - preceding and all subsequent files are ascii!
binary (* filenames in source(s) and target are matched
one-to-one.)
CTTY device
change MS-DOS I/O device
DATE dd-mm-yy
display and/or set date (numerical country-dependent format)
DEL ! ERASE pathname
delete file(s) - prompts if pathname is *.*
DIR pathname
display directory - filename and/or ext default to *
/p         - paginate
/w        - multi-column
DISKCOPY drive: drive:
copy disk sector-by-sector rather than file-by-file
EXIT
exit nested CLI
FIND “string” pathname
find and display lines containing string in file
/v         - lines NOT containing string
/c       - count lines only
/n       - display line numbers also
FORMAT drive:   (A: drive only)
/1         - single sided
/4         - use double rather than high density (40 tracks)
/8         - use 8 sectors of each track
/n:xx   - specifies xx sectors per track
/t:yy     - specifies yy tracks
/v         - prompt for volume label, up to 11 characters
/f:720   - format at 720 kb
LABEL drive: label   (A: drive only)
display, or edit volume label - 11 characters excluding
most specials
MKDIR (MD) path
make directoryMODE
interactively configure various options
MORE
paginates screen output
e.g. type filename | more
PATH path;path;...
display or set command search path(s) to be used after
cwd
PATH;
resets default to cwd only
PROMPT string
reset or set prompt.
Characters (each prefixed by $) mean:
$=$, t=time, d=date, p=cwd, v=version, n=drive,
g=>, l=<, b=!, _=CRLF, s=leading space, e=ESC (for ANSI driver)
RENAME (REN)pathname pathname
rename file(s) within a drive - wildcards are matched
one-to-one
RMDIR (RD) path
remove empty directory
SET variable=text
display all, set or clear MS-DOS variable - accessed as %variable%
SHARE
enable networked multi-access file locking
/f:nbytes - nbytes per file, need about 20 bytes per file,
default 2048
/l:nlocks - nlocks per file, default 20
SORT pathname pathname
sort lines of file alphabetically, ignoring case, to file or stdout; reads stdin by default
/r       - reverse order
/+n      - on n’th character in each line, default is first
SUBST drive: path   (A: drive only)
display substitutions, or substitute path by virtual drive
SYS drive :   (A: drive only)
copy hidden MS-DOS .sys files from default drive
TIME hours:minutes
display and/or set time using 24-hour format
TYPE pathname
output contents of a file, with tab spacing of 8
VER
display MS-DOS version
VERIFY on!off
display, or set!clear disk write verification
VOL drive:
display disk volume label

XCOPY pathname pathname 
                        copy directory tree
/a!m    - if archive bit set ! also clears in source
/d:date- modified on or after date only
/s!e        - copy subdirectories if not empty ! even if empty
/p           - prompt
/v           - verify
/w        - wait for keypress
If renamed to MCOPY it determines automatically whether
target is file or directory.
On-Line Command Help:Full details of all DOS commands can be seen by following the command with the switch /? For example,
DIR /?
gives a listing of all DIR options.

Command Editing:DOS commands are stored in a template and previous commands can be recalled, character by character enabling editing as required.

The template is accessed by the following keys:-
F1        -           get next character from template
F2 C    -           get characters up to but excluding character C
F3        -           get remaining characters from template
del       -           skip one character in template
F4 C    -           skip characters up to but excluding character C
ESC        -           clear command line
INS         -           toggle overwriting of template
F5        -           copy command to template for re-editing
F6        -           put ^Z in new template
The arrow keys may also be used to recall the previous
command.

Batch File Commands:All DOS commands may be used in batch files. Additionally, the following commands are useful for more advanced batch processes.

Arguments for batch files are accessed as ‘%1’ to ‘%9’.
ECHO on!off!message
display echo status, turn echoing on!off (default on)
or display message
FOR %%C IN (SET of items) DO command
C is any character other than 0-9, SET is e.g. list of files

GOTO LABEL
LABEL is any line of text, usually preceded by colon (:)
in first column, which makes MS-DOS ignore it other than as a label. Terminates if label not found
IF ERRORLEVEL number command
command executed if previous command returned exit
code >= number
IF string1  == string2 command
command executed if strings match
may be negated by NOT before condition
IF EXIST filename command
command executed if file exists
may be negated by NOT before condition
PAUSE comment
comment displayed only if echo on
REM comment
remark - ignored by MS-DOS
SHIFT
shift arguments - allows access to more than 9

SpcialCharacters:Several special characters may be used when referring to
directories and files:
\          =          root directory or a directory separator
=          current directory
=          parent directory
Wildcard characters may be used in filenames or extensions:
?           =          any character
*          =          any tail or extension
X:         -           switches to current working directory (cwd) on
drive X.

File Comparison Utility:The FC command enables comparison of two files:
FC pathname1 pathname2
compare two files, or two wildcarded sets of files
/a         - abbreviate output of ASCII comparison
/b         - force binary comparison (byte-by-byte)
/c       - ignore case
/L         - force ASCII comparison (line-by-line)
/Lb#     - use line buffer of # lines
/n       - display line numbers in ASCII mode
/t          - do not expand tabs - default expands to spacing
of 8
/w      - compress white space (tabs and spaces) to
single space (leading or trailing white space
always ignored)
/#       - # lines must match to re-synchronize else
regarded   different (default is 2)

I/O ControlDOS input and output may be controlled by the following control key sequences.   (^ = the CTRL key).
^C       -           abort current command
^H       -           destructive backspace
^J        -           linefeed - physical newline to input long lines
^N       -           toggle copying of terminal output to printer
^P        -           toggle redirection of terminal output to printer
^S        -           suspend/restart terminal output
^X       -           cancel current line, and output \-CR-LF
^Z        -           end of file

I/O Redirection   Input and output from commands or programs can be
redirected by using the following symbols:
>          send output to...
>>     append output to...
<          take input from...
|          pipe output to next input

Example:
pipe output from command a to input of command b:
command a | command b
send a directory listing to file filename:
DIR > filename
Using The DOS Editor:DOS includes a full-screen editor invoked by theEDIT  command (with or without a filename). To use this editor type:
EDIT (filename)
The editor provides pull-down menus, operated by the keyboard or mouse, and a help facility. Note that any changes made to a file overwrites the original, no backup is created...