问题
Can somebody remember what was the command to create an empty file in MSDOS using BAT file?
回答1:
echo. 2>EmptyFile.txt
回答2:
copy NUL EmptyFile.txt
DOS has a few special files (devices, actually) that exist in every directory, NUL being the equivalent of UNIX's /dev/null: it's a magic file that's always empty and throws away anything you write to it. Here's a list of some others; CON is occasionally useful as well.
To avoid having any output at all, you can use
copy /y NUL EmptyFile.txt >NUL
/y prevents copy from asking a question you can't see when output goes to NUL.
回答3:
type NUL > EmptyFile.txt
After reading the previous two posts, this blend of the two is what I came up with. It seems a little cleaner. There is no need to worry about redirecting the "1 file(s) copied." message to NUL, like the previous post does, and it looks nice next to the ECHO OutputLineFromLoop >> Emptyfile.txt that will usually follow in a batch file.
回答4:
Techniques I gathered from other answers:
Makes a 0 byte file a very clear, backward-compatible way:
type nul >EmptyFile.txt
idea via: anonymous, Danny Backett, possibly others, myself inspired by JdeBP's work
A 0 byte file another way, it's backward-compatible-looking:
REM. >EmptyFile.txt
idea via: Johannes
A 0 byte file 3rd way backward-compatible-looking, too:
echo. 2>EmptyFile.txt
idea via: TheSmurf
A 0 byte file the systematic way probably available since Windows 2000:
fsutil file createnew EmptyFile.txt 0
idea via: Emm
A 0 bytes file overwriting readonly files
ATTRIB -R filename.ext>NUL
(CD.>filename.ext)2>NUL
idea via: copyitright
A single newline (2 bytes: 0x0D 0x0A in hex notation, alternatively written as \r\n):
echo.>AlmostEmptyFile.txt
Note: no space between echo, . and >.
idea via: How can you echo a newline in batch files?
edit It seems that any invalid command redirected to a file would create an empty file. heh, a feature! compatibility: uknown
TheInvisibleFeature <nul >EmptyFile.txt
A 0 bytes file: invalid command/ with a random name (compatibility: uknown):
%RANDOM%-%TIME:~6,5% <nul >EmptyFile.txt
via: great source for random by Hung Huynh
edit 2 Andriy M points out the probably most amusing/provoking way to achieve this via invalid command
A 0 bytes file: invalid command/ the funky way (compatibility: unknown)
*>EmptyFile.txt
idea via: Andriy M
A 0 bytes file 4th-coming way:
break > file.txt
idea via: foxidrive thanks to comment of Double Gras!
回答5:
REM. > empty.file
回答6:
If there's a possibility that the to be written file already exists and is read only, use the following code:
ATTRIB -R filename.ext
CD .>filename.ext
If no file exists, simply do:
CD .>filename.ext
(updated/changed code according to DodgyCodeException's comment)
To supress any errors that may arise:
ATTRIB -R filename.ext>NUL
(CD .>filename.ext)2>NUL
回答7:
fsutil file createnew file.cmd 0
回答8:
One more to add to the books - short and sweet to type.
break>file.txt
break>"file with spaces in name.txt"
回答9:
You can use a TYPE command instead of COPY. Try this:
TYPE File1.txt>File2.txt
Where File1.txt is empty.
回答10:
You can also use SET to create a null byte file as follows
set x=x > EmptyFile.txt
Or if you don't want to create an extra variable reassign an existing variable like
set PROMPT=%PROMPT% > EmptyFile.txt
or like this:
set "PROMPT=%PROMPT%" > EmptyFile.txt
回答11:
The easiest way is:
echo. > Filename.txt
来源：https://stackoverflow.com/questions/210201/how-to-create-empty-text-file-from-a-batch-file