Thursday, February 27, 2014

Capturing ALL the output from a Windows command

Question: How do I capture all the output from a Windows command like MOVE? I want the exit code, the standard output, the error message, everything.

You can capture the exit code via %ERRORLEVEL%, and the standard output via MOVE ... >file.txt or >>file.txt, but that doesn't include error messages like "Access denied".

Sometimes, technical questions involving Microsoft products are best asked of StackOverflow Microsoft:

Google: how do i [do some thing]
In this case:
Google: how do i capture error messages from the move command

Happy, happy, happy...

Redirecting Error Messages from Command Prompt: STDERR/STDOUT talks about the magic 1> and 2> redirection operators, and how you can use 2>&1 to redirect STDERR to STDOUT plus 1> to redirect both to a file.

Here's a move.bat command file to test the technique: it MOVEs two files to a subfolder xxx, where one of the MOVE commands is going to fail because a read-only copy of the file already exists in the subfolder:
ERASE "diag.txt"
ECHO %DATE% %TIME% *** Testing diagnostics written from move.bat to diag.txt...    >>"diag.txt"
MOVE /Y "fff.txt" "xxx\fff.txt"                                                   1>>"diag.txt" 2>&1
ECHO %DATE% %TIME% *** MOVE fff.txt  ERRORLEVEL = %ERRORLEVEL%                     >>"diag.txt" 
MOVE /Y "ggg.txt" "xxx\ggg.txt"                                                   1>>"diag.txt" 2>&1
ECHO %DATE% %TIME% *** MOVE ggg.txt  ERRORLEVEL = %ERRORLEVEL%                     >>"diag.txt" 
ECHO %DATE% %TIME% *** ...all done                                                 >>"diag.txt" 
The Windows console output is now completely incomprehensible but that doesn't matter; this technique is intended for command files that run more-or-less unattended with ECHO OFF to suppress this crap stuff:

The resulting diag.txt file contains everything; Access is denied, 0 file(s) moved and ERRORLEVEL = 1:
Tue 02/25/2014 14:38:28.74 *** Testing diagnostics written from move.bat to diag.txt...    
Access is denied.
        0 file(s) moved.
Tue 02/25/2014 14:38:28.75 *** MOVE fff.txt  ERRORLEVEL = 1                      
        1 file(s) moved.
Tue 02/25/2014 14:38:28.76 *** MOVE ggg.txt  ERRORLEVEL = 0                      
Tue 02/25/2014 14:38:28.76 *** ...all done                                                  

1 comment:

Unknown said...

I always thought I have some pretty crafty batch files, but this info is a GREAT new find for me, and will eliminate some crude gymnastics to determine if some commands worked or not. Thanks!