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Success and failure are based on the Exit Code of the

In most cases the Exit Code is the same as theErrorLevel

For clarity the syntax on this page has spaces before and after the redirection operators, in practice you may want to omit those to avoid additional space characters being added to the output.Echo Demo Text Demofile.txt

When redirection is performed without specifying a numeric handle, the default is 1, i.e.will not redirect error messages.

Redirect any error message into a file

Append any error message into a file (

Redirect any CMD.exe error into a file

Redirect errors and output to one file

Redirect output and errors to separate files

This will fail! Redirect toNUL(hide errors)

Redirect output to file but suppress error (

Redirect output to file but suppress CMD.exe errors

Any long filenames must be surrounded in double quotes.

A CMD error is an error raised by the command processor itself rather than the program/command.

Redirection withor2will overwrite any existing file.

You can also redirect to a printer with PRNorLPT1

To prevent theandcharacters from causing redirection,escapewith a caret:^or^

Redirecting a string (or variable containing a string) will fail to work properly if there is a single numeral at the end, anything from 0 to 9.

One workaround for this is to add a space before the but that space will end up in the output.

Moving the redirection operator to the front of the line avoids this issue, but is undocumented syntax.

Create an empty file using the NUL device:

In a batch file the default behaviour is to read and expand variablesone lineat a time, if you use&to run multiple commands on a single line, then any variable changes will not be visible until execution moves to the next line. For example:

SET /P _cost=Enter the price: & ECHO %_cost%

This behaviour can be changed usingSETLOCAL EnableDelayedExpansion

Redirect multiple lines bybracketinga set of commands:

The CMD Shell can redirect ASCII/ANSI (the default) or Unicode (UCS-2 le) but not UTF-8.

This can be selected by launchingCMD /AorCMD /U

In Windows 7 and earlier versions of Windows, the redirection operator would strip many ExtendedASCII/Unicode characters from the output. Windows 10 no longer does this.

When a command is piped withbatch_commandthis will instantiate a new CMD.exe instance, in effect running:

C:\Windows\system32\cmd.exe /C /S /D batch_command

Any newline (CR/LF) characters in thebatch_commandwill be turned into&operators. (seeStackOverflow)

If thebatch_commandincludes any caretescapecharacters^they will need to be doubled up so that the escape survives into the new CMD shell.

Starting a new CMD shell also has a small (likely unnoticable) effect on performance.

For example, this syntax works, but would fail if the second or subsequent (piped) lines were indented with a space:

find def outfile.txt

Multi-line single commands with lots of parameters, can be indented as in this example:

If thefilenameorcommandis not found then redirection will set an Exit Code of 1

When redirecting the output of DIR to a file, you may notice that the output file (if in the same folder) will be listed with a size of 0 bytes. The command interpreter first creates the empty destination file, then runs the DIR command and finally saves the redirected text into the file.

The maximum number of consecutive pipes is2042

Another list of Files.txt DIR C:\

more text COPY nul empty.txt MEM /C

MyTextFile.txt SET _output=%_missing%

logfile.txt (TYPE logfile.txt newfile.txt) 2nul

Stupidity, outrage, vanity, cruelty, iniquity, bad faith, falsehood,

we fail to see the whole array when it is facing in the same direction as we ~ Jean Rostand (French Historian)

conIN$andconOUT$behave likestdinandstdout, or 0 and 1 streams but only with internal commands.

TYPE- Display the contents of one or more text files.

Successive redirections explained(1&3 ) – Stack Overflow.

Equivalent PowerShell:Redirection- Spooling output to a file, piping input.

Equivalent bash command (Linux):Redirection- Spooling output to a file, piping input.

Successive redirections explained(1&3 ) – Stack Overflow.插图