Microsoft KB Archive/69575

= COPY Concatenates Files Based on Command Syntax =

Article ID: 69575

Article Last Modified on 5/12/2003

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APPLIES TO


 * Microsoft MS-DOS 3.1
 * Microsoft MS-DOS 3.2 Standard Edition
 * Microsoft MS-DOS 3.21 Standard Edition
 * Microsoft MS-DOS 3.3 Standard Edition
 * Microsoft MS-DOS 3.3a
 * Microsoft MS-DOS 4.0 Standard Edition
 * Microsoft MS-DOS 4.01 Standard Edition
 * Microsoft MS-DOS 5.0 Standard Edition
 * Microsoft MS-DOS 5.0a
 * Microsoft MS-DOS 6.0 Standard Edition
 * Microsoft MS-DOS 6.2 Standard Edition
 * Microsoft MS-DOS 6.21 Standard Edition
 * Microsoft MS-DOS 6.22 Standard Edition

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This article was previously published under Q69575



SUMMARY
The MS-DOS COPY command can combine multiple files into one file. When you issue a command of the following form, COPY switches to ASCII mode and merges all source files into the target file

COPY  

where  can be of three forms: filenames with &quot;*&quot; or &quot;?&quot; (wildcard filenames), filenames separated with &quot;+&quot; (a specific, ordered list of files), or a combination of the two.

Because the COPY command recognizes  as being an absolute target, it assumes that you want to concatenate the multiple files into a single new file. This means that COPY switches to ASCII mode where end-of- file (EOF) markers are acknowledged.



MORE INFORMATION
This behavior is sometimes confusing when you know that only one file exists that matches the source filename and you formulate a COPY command that assumes that knowledge. If you issue a command as in the following example, COPY still switches into merge mode and copies the file as if it were ASCII:

COPY C:\COMM*.* A:\COMMAND.COM

Although you intended to copy only COMMAND.COM from the root of drive C to the root of drive A, COPY actually tries to concatenate COMMAND.COM with some other file before it discovers that the some other file does not exist. The resulting file is shorter than the original because COPY stopped at the first 0x01A byte that it found. (In the case of COMMAND.COM, this is usually within the first ten characters, so this particular example occurs quite often).

Additional query words: 6.22 3.20 3.21 3.30 3.30a 4.00 4.01 5.00 5.00a 6.00 6.20 truncate

Keywords: KB69575

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