Batch Error Output Redirect
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Batch Redirect Output To Variable
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Linux Error Output Redirect
Utilities Resource Kits Compilers Editors Code Generators Regular Expressions Automation Tools VBScript Add-Ons Visual Studio Printing Tools Inventory Tools Shell Extensions File Viewers Backup Security The making Of... Miscellaneous Tweaks Web Stuff Conversions My Photo Galleries About This Site Disclaimer News FAQ Search What's New Objective Site Policy Your Preferences Credits The Making Of... Contact Failed Mail Donate Redirection Redirection command > file Write standard output of command to file command 1> file Write standard output of command to file (same as previous) command 2> file Write standard error of command to file (OS/2 and NT) command > file 2>&1 Write both standard output and standard error of command to file (OS/2 and NT) command >> file Append standard output of command to file command 1>> file Append standard output of command to file (same as previous) command 2>> file Append standard error of command t
commandB commandA & commandB Run commandA and then run commandB commandA && commandB Run commandA, if it succeeds then run commandB commandA || standard error output redirect commandB Run commandA, if it fails then run commandB commandA && commandB || batch redirect stderr to stdout commandC If commandA succeeds run commandB, if it fails commandC Success and failure are based on the Exit Code of
Dos Command Redirect Output
the command. In most cases the Exit Code is the same as the ErrorLevel Numeric handles: STDIN = 0 Keyboard input STDOUT = 1 Text output STDERR = 2 Error text output UNDEFINED http://www.robvanderwoude.com/redirection.php = 3-9 command 2> filename Redirect any error message into a file command 2>> filename Append any error message into a file (command)2> filename Redirect any CMD.exe error into a file command > file 2>&1 Redirect errors and output to one file command > fileA 2> fileB Redirect output and errors to separate files command 2>&1 >filename This will fail! Redirect to NUL (hide errors) command http://ss64.com/nt/syntax-redirection.html 2> nul Redirect error messages to NUL command >nul 2>&1 Redirect error and output to NUL command >filename 2> nul Redirect output to file but suppress error (command)>filename 2> nul 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 with > or 2> will overwrite any existing file. You can also redirect to a printer with > PRN or >LPT1 Multiple commands on one line In a batch file the default behaviour is to read and expand variables one line at 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 using SETLOCAL EnableDelayedExpansion Creating a new file Create empty files using the NUL device: Type NUL >EmptyFile.txt or Copy NUL EmptyFile.txt To prevent the > and < characters from causing redirection, escape with a caret: ^> or ^< Redirect multiple lines by bracketing a set
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring http://stackoverflow.com/questions/1420965/redirect-stdout-and-stderr-to-a-single-file developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; http://blog.crankybit.com/redirecting-output-to-a-file-in-windows-batch-scripts/ it only takes a minute: Sign up Redirect stdout and stderr to a single file up vote 357 down vote favorite 97 I'm trying to redirect all output (stdout + stderr) of a DOS command to a single file: error output C:\>dir 1> a.txt 2> a.txt The process cannot access the file because it is being used by another process. Is it possible, or should I just redirect to two separate files? windows command-line cmd pipe share|improve this question edited Oct 9 '15 at 19:39 Peter Mortensen 10.2k1369107 asked Sep 14 '09 at 11:20 ripper234 66.2k165463746 2 TechNet: Using command redirection operators (answers this better than any of the answers here). –Martin Prikryl May 11 at 6:09 add a error output redirect comment| 6 Answers 6 active oldest votes up vote 553 down vote accepted You want: dir > a.txt 2>&1 share|improve this answer answered Sep 14 '09 at 11:23 Anders Lindahl 24.7k55275 10 thanks for this, didn't know that this unix shell syntax works for DOS too! –chaindriver Aug 14 '12 at 17:00 11 this is great for hiding all output.. net stop w3svc >NUL 2>&1.. thanks! –wasatchwizard Apr 4 '13 at 17:55 1 @wasatchwizard Ithink I had trouble with that, but >NUL 2>NUL worked fine –FrinkTheBrave Aug 4 '14 at 8:24 4 If there is a Handle, there cannot be a space between the Handle (i.e. 2) and the redirect operator (i.e. >). Therefore 2> 2.txt works (or 2> &1) 2 > 2.txt does not; 2 > &1 does not. –The Red Pea Apr 3 '15 at 21:41 Reference document from Microsoft: support.microsoft.com/en-us/kb/110930 –Jonathan Benn Feb 3 at 18:58 | show 1 more comment up vote 101 down vote Anders Lindahl's answer is correct, but it should be noted that if you are redirecting stdout to a file and want to redirect stderr as well then you MUST ensure that 2>&1 is specified AFTER the 1> redirect, otherwise it will not work. REM *** WARNING: THIS WILL NOT REDIRECT STDERR TO STDOUT **** dir 2>&1 > a.txt share|improve this answer edited Oct 9 '15 at 19:40 Peter Mortensen 10.2k1369107 answ
Operators page provides the factual information on how to do redirection, but actual implementation gets a bit confusing for anything beyond command > filename.txt. Here's a rundown on how to do some useful things. I'm not going to cover every aspect of redirection, but I'll point you to the cases I find myself in most often. The basics. You want to generate either a log file or a file that you will be executing after you're done generating it. You'll likely be using a combination of echo commands as well as some output from a handful of commands. Welcome to the > and >> operators. The first will send the output to a file and erase its existing contents; the second will append the output to the file. Examples: # This will send the dir command's output to a fresh file: dir > myfile.txt # Here I will create a fresh file with an echo command, # and append the dir output to that: echo Here is a directory > myfile.txt dir >> myfile.txt Redirection for logging. This is a great way to make log files, which can even have the date and time with a simple improvement over that last example: echo %date%, %time%: Listing a directory. > myfile.txt dir >> myfile.txt Using this technique, you can log not just what your batch scripts are trying to do, but what the results are. For instance, let's say we're generating a batch script that automatically creates accounts and drops them in a group. If I'm doing this in AD, I might have code like this: # Add user "joe" to the "MyGroup" group. net group MyGroup joe /add To log the result of this, I might try: net group MyGroup joe /add >> AddAccts.log Better error logging. When this command succeeds, it outputs, "This command completed successfully." It will output this to the log file, and you know the net group command succeeded. However, if there were errors, it will output, "The command completed with one or more errors." However, the standard output doesn't include the actual error messages, even though you can see them outputting to the screen. This is because there is a separate error stream, and by default, the redirection operator only streams the standard output. This is where the >& operator comes in. This will pass the output from one "stream", or "handle" into another. This means you can take a command's error stream, and pass it into its output stream, s