CMD Echo命令仅保留最后一行文本

Question

I'm creating a batch file and I'm having trouble with the following command:

    echo Hello & echo.World > Text.txt

Whenever I do this command the output only shows the last line, like so:

World

But if I just do the above command in CMD without writing to a file, it appears perfectly in the command prompt. I have complete access over my file but I still can't seem to be able to write the whole text.

Answer 1

In batch, the > operator has higher precedence than the & operator, so your example is only redirecting the last command echo.World to the file. The first command is still outputting to the console.

To redirect multiple commands, you can surround them with parentheses.

(echo Hello & echo.World) > Text.txt

Answer 2

In batch & is a command-separator. You can produce the same result by using two separate echo lines.

echo Hello & echo.World > Text.txt

executes as two independent commands,

echo Hello echo.World > Text.txt

which would report Hello to the console and write World to the file (you didn't mention that Hello appeared on the console...)

Note that > creates a new file whereas >> appends to any existing file (or creates a new file) so

echo Hello > Text.txt
echo.World > Text.txt

would first write Hello to a new file, then overwrite it with World .

To append the second line, you'd need

echo Hello > Text.txt
echo.World >> Text.txt

or, on one line,

echo Hello > Text.txt&echo.World >> Text.txt

A parenthesised statement-sequence (aka a "block") is regarded as one complex statement, so

(echo Hello &echo.World)> Text.txt

would create a new file containing both lines, whereas

(echo Hello &echo.World)>> Text.txt

would append the two lines to any existing file.

Note also that the trailing spaces before the > will also be written to the file.

Be very careful about > and >> . if the command you execute is

echo Hello 1> Text.txt

then hello Space will be written to the file.

If a message terminating with Space a single digit is written to a file, then well, probably nothing will appear. When we have this situation, the digit immediately before the > determins which 'logical device output will be used. The useful ones here are 1 (standard output) and 2(standard error) so you can redirect errormessages using output will be used. The useful ones here are 1 (standard output) and 2(standard error) so you can redirect errormessages using 2>errorreports.txt` for instance.

If you have this situation, you can overcome this characteristic by using

> Text.txt echo Hello 1