commands.txt

Dos6.22安装软件,现在使用Dos的朋友不是很多了,希望能大家一些方便.

   command. 
/T:time Backs up only files modified at or after the specified time. 
   The time format depends on the setting you are using for the COUNTRY 
   command. 
/L[:[drive:][path]logfile] 
   Creates a log file and adds an entry to that file to record the 
   backup operation. If you do not specify a location for the log file, 
   BACKUP puts the file in the root directory of the source drive. If 
   you do not specify logfile, BACKUP names the file BACKUP.LOG. You 
   should not specify a removable drive (such as a floppy disk drive) 
   for this parameter; but once the backup is complete, you can copy the 
   log file to a floppy disk. 

NOTES
-----

Backing up onto a disk with files
---------------------------------
Unless you use the /A switch, BACKUP deletes old files (including 
read-only files) from a backup disk before adding new files to it. 

Backup log file 
---------------
If you use the /L switch and do not specify a name and location for 
the log file, the BACKUP command adds a file named BACKUP.LOG to the 
root directory of the source drive. If the BACKUP.LOG file already 
exists, BACKUP adds the current entry to the file. A backup log-file 
entry uses the following format: 

o The date and time of the backup appear on the first line. 
o Each filename appears on a separate line with the number of 
  the backup disk that contains the file. 

The backup log file can assist you later, when you need to identify 
the files you want to restore. The RESTORE command always returns a 
file to the original directory or subdirectory recorded in the backup 
log, creating the subdirectory if necessary. 

Labeling backup disks 
---------------------
It is important to label and number backup disks consecutively. As each 
disk is filled, BACKUP prompts you for the next disk. When you restore 
files, you need to insert the backup disks into the disk drive in the 
same sequence. To check the sequence of backup disks (MS-DOS version 3.3 
or later), use the DIR command to check the disk number. 

BACKUP and system files 
-----------------------
The BACKUP command cannot back up the system files IO.SYS, MSDOS.SYS, 
and COMMAND.COM. You can use the SYS command to copy these files onto 
a floppy disk. 

Using an old version of the RESTORE command 
-------------------------------------------
You cannot use an old version of the RESTORE command (MS-DOS version 
3.2 or earlier) for files backed up with MS-DOS version 3.3 or later. 
If you attempt this, MS-DOS displays the following message: 
   
   Source does not contain backup files 
   
This error occurs because the format of old backup files differs from 
the format of files backed up with MS-DOS versions 3.3 and later. 

Using BACKUP with networks or redirected drives or directories 
--------------------------------------------------------------
If you are sharing files on a network, you can back up only those 
files to which you have access. You should not use BACKUP with a drive 
that has been redirected with the ASSIGN, JOIN, or SUBST command. If you 
do, the RESTORE command may not be able to restore the files. 

Backup exit codes 
-----------------
The following list shows each exit code and a brief description of its 
meaning: 

0    The backup was successful.

1    No files were found to back up.

2    Some files were not backed up because of file-sharing conflicts.

3    The user pressed CTRL+C to stop the process.

4    The process stopped because of an error.

You can use the ERRORLEVEL parameter on the IF command line in a 
batch program to process exit codes returned by the BACKUP command. 
 
EXAMPLES
--------
Suppose you want to back up all the files in the \PUBLIC\SMITH directory 
on drive C onto a blank, formatted disk in drive A. To do so, type the 
following: 

BACKUP C:\PUBLIC\SMITH\*.* A:
 
Suppose you need to back up all files in the \PUBLIC\SMITH directory 
on drive C onto a 720K floppy disk in drive B. If the floppy disk is 
unformatted, BACKUP formats it before backing up any files. Because the 
/S switch is not specified in the following command, files in 
subdirectories are not backed up: 

BACKUP C:\PUBLIC\SMITH\*.* B: /F:720K

To write a simple batch program named SMITH that supports the BACKUP 
command's exit codes and the /S switch, you can type the following 
commands by using MS-DOS Editor: 

echo off
rem Smith's backup command
backup c:\public\smith\*.* b: /s
if errorlevel 4 goto error
if errorlevel 3 goto abort
if errorlevel 2 goto conflict
if errorlevel 1 goto no_files
if errorlevel 0 goto success
:error
echo Backup stopped the process due to an error
goto exit
:abort
echo You just pressed CTRL+C to stop the backup
goto exit
:conflict
echo One or more files were not backed up due to a sharing conflict
goto exit
:no_files
echo Sorry, but there were no files to back up
goto exit
:success
echo The backup was successful
goto exit
:exit

CHOICE----------------------------------------------------------------------

A command used by the Setup program. The CHOICE.COM file is the same one
included with MS-DOS 6.22.

COMP------------------------------------------------------------------------

Compares the contents of two files or sets of files byte by byte. 

COMP can compare files on the same drive or on different drives, in 
the same directory or in different directories. As COMP compares the 
files, it displays their locations and filenames.
 
SYNTAX 
------
COMP [data1] [data2] [/D] [/A] [/L] [/N=number] [/C]

PARAMETERS
---------- 
data1 
   Specifies the location and name of the first file or set of files 
   you want to compare. You can use wildcards (* and ?) to specify 
   multiple files. 

data2 
   Specifies the location and name of the second file or set of files 
   you want to compare. You can use wildcards (* and ?) to specify 
   multiple files. 

SWITCHES
--------
/D 
   Displays differences in decimal format. (The default format is 
   hexadecimal.) 

/A 
   Displays differences as characters. 

/L 
   Displays the number of the line on which a difference occurs, 
   instead of displaying the byte offset. 

/N=number 
   Compares the first number of lines of both files, even if the 
   files are different sizes. 

/C 
   Performs a comparison that is not case-sensitive. 

NOTES
-----

Comparing files with the same names
-----------------------------------
The files you want to compare can have the same filename, provided 
they are in different directories or on different drives. If you do 
not specify a filename for data2, the default filename for data2 is 
the same as the filename in data1. You can use wildcards (* and ?) 
to specify filenames. 

Special cases for data1 and data2 
---------------------------------
If you omit necessary components of either data1 or data2 or if you 
omit data2, COMP prompts you for the missing information. If data1 
contains only a drive letter or a directory name with no filename, 
the default filename for data1 is *.*. Therefore, COMP compares all 
the files in the specified directory to the file specified in data2. 
If data2 contains only a drive letter or a directory name, the 
default filename for data2 is the same as that in data1. 

How the COMP command identifies mismatching information 
-------------------------------------------------------
During the comparison, COMP displays messages to identify the 
locations of unequal information in the two files. Each message 
indicates the offset memory address of the unequal bytes and the 
contents of the bytes themselves (in hexadecimal notation unless 
you specify the /A or /D switch). The message has the following 
format: 

   Compare error at OFFSET xxxxxxxx
   file1 = xx
   file2 = xx

After 10 unequal comparisons, COMP stops comparing the files and 
displays the following message: 

   10 Mismatches