Windows cmd redirect output to file

Background info from Microsoft documentation

While the accepted answer to this question is correct, it really doesn’t do much to explain why it works, and since the syntax is not immediately clear I did a quick www search to find out what was actually going on. In the hopes that this information is helpful to others, I’m posting it here.

Taken from the Microsoft documentation page:
Redirecting error messages from Command Prompt: STDERR/STDOUT

Summary

When redirecting output from an application using the > symbol, error messages still print to the screen. This is because error messages are often sent to the Standard Error stream instead of the Standard Out stream.

Output from a console (Command Prompt) application or command is often sent to two separate streams. The regular output is sent to Standard Out (STDOUT) and the error messages are sent to Standard Error (STDERR). When you redirect console output using the > symbol, you are only redirecting STDOUT. In order to redirect STDERR, you have to specify 2> for the redirection symbol. This selects the second output stream that is STDERR.

Example

The command dir file.xxx (where file.xxx does not exist) will display the following output:

Volume in drive F is Candy Cane Volume Serial Number is 34EC-0876
File Not Found

If you redirect the output to the NUL device using dir file.xxx > nul, you will still see the error message:

File Not Found

To redirect the error message to NUL, use the following command:

dir file.xxx 2> nul

Or, you can redirect the output to one place, and the errors to another.

dir file.xxx 1> output.msg 2>&1

You can print the errors and standard output to a single file by using the &1 command to redirect the output for STDERR to STDOUT and then sending the output from STDOUT to a file:

dir file.xxx 1> output.msg 2>&1

When we use > to redirect Standard Output, CMD.EXE interprets this as 1>, as can be seen by writing and running this one-line batch file «test.bat»:

DIR > NUL

Now run test.bat in CMD.EXE and watch the result:

C:>test.bat

C:>DIR  1>NUL

C:>_

It looks like CMD.EXE uses 1 for Standard Output and 2 for Standard Error.
We’ll see how we can use this later.

Nothing is impossible, not even redirecting the Console output.

Unfortunately, it can be done only in the old MS-DOS versions that came with a CTTY command.

The general idea was this:

CTTY NUL
ECHO Echo whatever you want, it won't be displayed on screen no matter what.
ECHO By the way, did I warn you that the keyboard doesn't work either?
ECHO I suppose that's why CTTY is no longer available on Windows systems.
ECHO The only way to get control over the computer again is a cold reboot,
ECHO or the following command:
CTTY CON

A pause or prompt for input before the CTTY CON command meant one had to press the reset button!

Besides being used for redirection to the NUL device, with CTTY COM1 the control could be passed on to a terminal on serial port COM1.

A safer way to redirect STARTed commands’ output would be to create and run a «wrapper» batch file that handles the redirection.
The batch file would look like this:

command > logfile

and the command line would be:

START batchfile

page last modified: 2016-09-19

You haven’t shown the command you are using that is failing. If you show it in your question, it might be easier to find a solution for you.

I expect your command is something like this:

C:>foo.exe|c:Program Files (x86)somethingtest.txt

The error you are receiving is somewhat of a clue:

'c:/Program' is not recognized as an internal or external command, operable program or batch file.

First:
... is not recognized as an internal or external command, operable program or batch file.

This typically happens when you try to redirect to a file using a | instead of a >.

Second:
'c:/Program' ...

When specifying a filename (or path) that contains spaces, you must surround it in double-quote marks ("...") . This is because when the OS is determining the file to redirect to, it will stop looking for the filename when it encounters an unquoted space: "c:/Program".

Try this:

foo.exe>"c:Program Files (x86)somethingtest.txt"

If the above doesn’t work to capture the output from foo.exe to the text file, then there is another possibility…

If the program foo.exe is writing its output to STDERR instead of STDOUT, the output of foo.exe will not be captured by using simple redirection with a single >. You would have to do it like this:

foo.exe>"c:Program Files (x86)somethingtest.txt" 2>&1

Edit:

Here is an explanation of file redirection and the 2>&1 notation.

When a program writes to the terminal, it can write to one of two Streams.

1. Stream 1 is referred to as STDOUT or Standard-Output. Typically, programs write their «Normal» output to stream 1.

2. Stream 2 is referred to as STDERR or Standard-Error. Typically, programs write their «Error» output (error and warning messages) to stream 2.

Whether a program writes a particular output to STDOUT or STDERR is determined by the programmer and how they wrote the program. Some programs are written to send all output (normal output and errors) to STDOUT.

When a program is run with no output redirection, all normal and error output is sent to the terminal screen without any distinction between what is STDOUT output or STDERR output.

When you do «normal» redirection with a single > like this:

foo.exe > "c:Program Files (x86)somethingtest.txt"

you are not specifying which Stream is being redirected to the file, so Stream 1 is assumed.

It’s the same as if you typed it like this:

foo.exe 1> "c:Program Files (x86)somethingtest.txt"

This tells the command interpreter (cmd.exe) to capture the program output for STDOUT (Stream 1) to the specified filename. The 1 in 1> refers to Stream 1.

In this case all the normal program is captured to the file, but if the program writes to STDERR (Stream 2), that output will not be captured and will be shown on the screen. This is generally the «desired» way to do it so that while you are capturing the normal program output, you can see on the screen if an error occurs.

If you want to capture «Normal» output to one file, and «Error» output to a different file you can do it like this:

    foo.exe > "c:output.txt" 2> "C:error.txt"
or
    foo.exe 1> "c:output.txt" 2> "C:error.txt"

If you want the «Normal» output and the «Error» output to be captured to the same file, you can specify it like this:

foo.exe > "c:output.txt" 2>&1

This is basically a «shorthand» way of specifying it and it means to redirect Stream 1 to the specified file, and to also redirect Stream 2 to the same «place» (file) as Stream 1.

Edit:

Pacerier asked:

Is there any difference between foo.exe > «c:output.txt» 2>&1 and foo.exe > «c:output.txt» 2>»c:output.txt»? Are they identical?

Short answer: You would think they are identical, but no. They are different.

With redirection using >"filename.ext", 1>"filename.ext", or 2>"filename.ext", the > causes the output to be written to a new file named «filename.ext». If the file «filename.ext» already exists, it will be deleted first.

So, using:

foo.exe > «c:output.txt» 2>»c:output.txt»

causes a «conflict» where both redirections are trying to write to the same file and both are trying to delete the file if it already exists. This will likely cause undesired behavior. Generally, one or the other, or both, of the outputs will NOT be captured fully, or predictably.

The actual result will depend on the operating system and version, and may also depend on the command being executed. What will likely happen is:

1 The output sent to one of the redirections will be captured or partially captured, and the output sent to other redirection will be lost.
2 The operating system will complain about the command and neither of the outputs will be captured (fully).
3 Undefined, undesired, unpredictable, unexpected behavior.

On Windows 7 and likely on Windows Vista/8/10, and possibly on Windows XP, the operating system will complain about command and the command will be canceled.

For example (Windows 7): I have a folder named: "C:Tempemptyfolder" and a file named «nonexistantfile» doesn’t exist there.

C:>cd "Tempemptyfolder"

C:Tempemptyfolder>dir nonexistantfile>output.txt
File Not Found

C:Tempemptyfolder>type output.txt
 Volume in drive F is FFFFx1tb
 Volume Serial Number is 4011-A5C6

 Directory of C:Tempemptyfolder

C:Tempemptyfolder>

In this case, using one redirection (>output.txt), the output of the dir command is captured the the file: output.txt, and the error message File Not Found is shown on the screen… this is the expected behavior.

Now, using both redirections («>file» AND «2>file»):

C:Tempemptyfolder>dir nonexistantfile>output.txt 2>output.txt
The process cannot access the file because it is being used by another process.
C:Tempemptyfolder>type output.txt

C:Tempemptyfolder>

In this case, the operating system complained that the (outout) file is already in use. And the file «output.txt» ends up empty (0 bytes), and the output for both of the redirections was lost.

Now, lastly, using both redirections («>file» AND «2>&1»):

C:Tempemptyfolder>dir nonexistantfile>output.txt 2>&1

C:Tempemptyfolder>type output.txt
 Volume in drive C is CCCCCCCC
 Volume Serial Number is 1234-ABCD

 Directory of C:Tempemptyfolder

File Not Found

C:Tempemptyfolder>

In this case, «>file» causes the output for «stream 1» («standard output») to be captured to the file. And «2>&1» causes the output for «stream 2» («error output») to be sent through the already redirected «stream 1», and to also be captured to the (same) file.

It is also worth noting that the order is important. Reversing the order like this:

dir nonexistant 2>&1 >output.txt

is not the same and will probably not give you the desired result.

In this case, «2>&1», which is seen and precessed first, causes the output for «stream 2» («error output») to be redirected to the place where «stream 1» is currently directed to, which at that moment, is (by default), the screen. And «>file» causes the output for «stream 1» («standard output») to be captured to the file. The end result, is that the output of the command («stream 1») will be captured to the file, but the error output («stream 2»), will still go to the screen (not to the file).

Use a redirection operator to redirect the output of a command to a file. All the information displayed in Command Prompt after running a command can be saved to a file, which you can reference later or manipulate however you like.

How to Use Redirection Operators

While there are several redirection operators, two, in particular, are used to output the results of a command to a file: the greater-than sign (>) and the double greater-than sign (>>).

The easiest way to learn how to use these redirection operators is to see some examples:

ipconfig /all > networksettings.txt

In this example, all the information normally seen on screen after running ipconfig /all, is saved to a file by the name of networksettings.txt. It’s stored in the folder to the left of the command, the root of the D: drive in this case.

The > redirection operator goes between the command and the filename. If the file already exists, it’ll be overwritten. If it doesn’t already exist, it will be created.

ping 192.168.86.1 > "C:UsersjonfiDesktopPing Results.txt"

Here, when the ping command is executed, Command Prompt outputs the results to a file by the name of Ping Results.txt located on the jonfi user’s desktop, at C:UsersjonfiDesktop. The entire file path in wrapped in quotes because a space involved.

Remember, when using the > redirection operator, the file specified is created if it doesn’t already exist and is overwritten if it does exist.

The Append Redirection Operator

The double-arrow operator appends, rather than replaces, a file:

ipconfig /all >> \serverfilesofficenetsettings.log

This example uses the >> redirection operator which functions in much the same way as the > operator, only instead of overwriting the output file if it exists, it appends the command output to the end of the file.

Here’s an example of what this LOG file might look like after a command has been exported to it:

The >> redirection operator is useful when you’re collecting similar information from different computers or commands, and you’d like all that data in a single file.

The above redirection operator examples are within the context of Command Prompt, but you can also use them in a BAT file. When you use a BAT file to pipe a command’s output to a text file, the exact same commands described above are used, but instead of pressing Enter to run them, you just have to open the .BAT file.

Use Redirection Operators in Batch Files

Redirection operators work in batch files by including the command just as you would from the Command Prompt:

tracert yahoo.com > C:yahootracert.txt

The above is an example of how to make a batch file that uses a redirection operator with the tracert command.

The yahootracert.txt file (shown above) will be created on the C: drive several seconds after executing the sample.bat file. Like the other examples above, the file shows everything Command Prompt would have revealed if the redirection operator wasn’t used.

Thanks for letting us know!

The ‘>’ operator is used to redirect the output to a new file, the ‘>>’ is used to redirect the output and append to the file.
Now both the STDOUT and STDERR are written to the console by default. Output from a console (Command Prompt) application or command is often sent to two separate streams. The regular output is sent to Standard Out (STDOUT) and the error messages are sent to Standard Error (STDERR). When you redirect console output using the “>” symbol, you are only redirecting STDOUT. In order to redirect STDERR you have to specify “2>” for the redirection symbol. This selects the second output stream which is STDERR.

For Example, running the dir command on a file gives both stdout and stderr like below:

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C: dir nosuchfile.txt
 Volume in drive C has no label.
 Volume Serial Number is B8A1-5FD1
 
 Directory of C:
 
File Not Found

Here the “File Not Found” message is the STDERR and the rest was for STDOUT. Now if you want to redirect the whole output to a file, just running the command dir nosuchfile.txt > result.log will not cut it. You need to do one of the following:

Sending the STDERR and STDOUT to different files:

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dir nosuchfile.txt > out.log 2>error.log

Sending the STDERR and STDOUT to Same file:

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dir nosuchfile.txt > alloutput.log 2>&1

Here the 2>&1 instructs that the STDERR to be redirected to STDOUT which is in-turn writing out to alloutput.log file.

“Know thy commands.”
-Rushi

Перенаправление ввода-вывода в cmd

Перенаправление стандартных ввода-вывода и ошибок

С помощью переназначения устройств ввода/вывода одна программа может направить свой вывод на вход другой или перехватить вывод другой программы, используя его в качестве своих входных данных. Таким образом, имеется возможность передавать информацию от процесса к процессу при минимальных программных издержках. Практически это означает, что для программ, которые используют стандартные входные и выходные устройства, операционная система позволяет:

• выводить сообщения программ не на экран (стандартный выходной поток), а в файл или на принтер (перенаправление вывода);
• читать входные данные не с клавиатуры (стандартный входной поток), а из заранее подготовленного файла (перенаправление ввода);
• передавать сообщения, выводимые одной программой, в качестве входных данных для другой программы (конвейеризация или композиция команд).

Из командной строки эти возможности реализуются следующим образом. Для того, чтобы перенаправить текстовые сообщения, выводимые какой-либо командой из командной строки, в текстовый файл, нужно использовать конструкцию команда > имя_файла. Если при этом заданный для вывода файл уже существовал, то он перезаписывается (старое содержимое теряется), если не существовал создается. Можно также не создавать файл заново, а дописывать информацию, выводимую командой, в конец существующего файла. Для этого команда перенаправления вывода должна быть задана так: команда >> имя_файла. С помощью символа < можно прочитать входные данные для заданной команды не с клавиатуры, а из определенного (заранее подготовленного) файла: команда < имя_файла

Примеры перенаправления ввода/вывода в командной строке

Приведем несколько примеров перенаправления ввода/вывода.

1. Вывод результатов команды ping в файл  ping ya.ru > ping.txt

2. Добавление текста справки для команды XCOPY в файл copy.txt: XCOPY /? >> copy.txt

В случае необходимости сообщения об ошибках (стандартный поток ошибок) можно перенаправить в текстовый файл с помощью конструкции команда 2> имя_файла В этом случае стандартный вывод будет производиться на экран. Также имеется возможность информационные сообщения и сообщения об ошибках выводить в один и тот же файл. Делается это следующим образом: команда > имя_файла 2>&1

Например, в приведенной ниже команде стандартный выходной поток и стандартный поток ошибок перенаправляются в файл copy.txt: XCOPY A:1.txt C: > copy.txt 2>&1

Windows Command-line tools are great for troubleshooting, as well as automation. But, if you’re stumped when a tech support guy on the phone asks you to run a built-in console command and copy the output displayed for diagnosing a problem, these Command Prompt basics will come in handy.

This post explains how to copy or redirect Command Prompt output to a file or the clipboard.

Opening a Command Prompt window

To open a Command Prompt window, press WinKey + R to launch the Run dialog. Type in cmd.exe and press Ok. In Windows 8.1 and Windows 10, you can right-click Start and click Command Prompt. There are several other ways to open Command Prompt.

If the console tool you’re running or the operation you’re performing requires administrative privileges, you need to open Command Prompt as administrator (also known as “elevated” Command Prompt.)

In the Command Prompt window, type in the command you want to run. For example, someone who’s helping you wants to know your system information by running SystemInfo command, type systeminfo and press ENTER.

Copying the output to clipboard

To copy the command prompt output to the clipboard, use one of the methods.

Using Keyboard: Press Ctrl + A to select all text, and press ENTER to copy it to the clipboard.

Using the Edit menu: Right-click the Command Prompt title bar → Edit → Select All. Repeat the same, and this time, select Copy from the Edit menu.

Using Clip.exe console tool: The Clip.exe console tool is built-in to Windows, starting with Windows Vista and up to Windows 10. This tool copies the data redirected or passed to it, into the clipboard. You can redirect the output of your console tool or command to the clipboard using the built-in Clip.exe tool by piping the output. The command you’d run is:

systeminfo |clip

That would copy the output of the systeminfo command to the Windows Clipboard. This is done by Clip.exe receiving the command-line output directly.

Once the output is sent to the clipboard, you can paste it into a text editor. For example, you can open Notepad and paste (Ctrl + V) the contents there.

Redirecting the output to a new file

You can redirect the command-line output to a file instead of Clipboard. This method can be useful if the output is too lengthy, containing several hundreds of lines that can easily exceed the Command Prompt window’s screen buffer size. To output the results to a file, use this syntax/examples:

systeminfo >%temp%systeminfo.txt

That would create a file named systeminfo.txt in the user’s Temp folder. To write the output to a file on your desktop, you’d use:

systeminfo >%userprofile%desktopsysteminfo.txt

Redirecting the output to a file by appending

The previous command would create a new file or erase the previous file (if one exists with the same name). If you want to append the command-line output to a file, use double greater-than symbols >>, as below:

ipconfig >>%userprofile%desktopsysteminfo.txt
systeminfo >>%userprofile%desktopsysteminfo.txt

That would output the contents of Ipconfig and Systeminfo commands to the same file. If a file exists with the same name systeminfo.txt, it would be used. Otherwise, a new file would be created.

Another example

ipconfig >%userprofile%desktopinfo.txt
sc query wuauserv >>%userprofile%desktopinfo.txt
dir d:tools*.exe >>%userprofile%desktopinfo.txt
dir C:WindowsSystem32Tasks /s /b >>%userprofile%desktopinfo.txt

The first command would create a new file (as a single > symbol is used) named info.txt. Subsequent commands would output the results to the existing info.txt file (double >> symbol).

Take a Screenshot

In some cases, you may not require the text output, and a screenshot is sufficient. Win + PrntScrn keystroke is used to take a screenshot quickly in Windows 8 and 10. Or use the excellent built-in Snipping Tool. Check out How to Take a Screenshot in Windows for a detailed guide.

I hope this guide helped you learn how to copy or redirect Command Prompt output to a file or the clipboard.