The COPY command can concatenate a file onto an existing file when
used in the form:
In this example, the contents of FILE2 are appended to FILE1, leaving
FILE2 unchanged. When copying in this mode, the COPY command switches
to ASCII mode where the ^Z (0x01A) end-of-file marker is honored.
Therefore, with the above command, the /b forces the COPY command into
binary mode, the filename is the file to be updated, the + (plus sign)
indicates that a file is to be appended, and the ,, (commas) are
placeholders for the remaining parameters (which are not included in
this example). Because the file to be appended is not specified, the
COPY command will append nothing and only update the time and date
stamps for the file.
The following batch file, TOUCH.BAT, can be used to automate the
if %1.==. goto end
if not exist %1 goto end
copy /b %1 +,, > nul
echo %1 touched!
This batch file requires one parameter, the file to be "touched." If
the parameter is not supplied, line 2 will cause the batch file to
exit without doing anything. If the specified file does not exist,
line 3 will cause the batch file to exit also.