42

I use 7-Zip to compress files inside a batch file like this:

...\right_path\7z a output_file_name.zip file_to_be_compressed

I got the following output:

7-Zip 4.65  Copyright (c) 1999-2009 Igor Pavlov  2009-02-03
Scanning

Creating archive output_file_name.zip

Compressing  file_to_be_compressed

Everything is Ok

Is it possible to disable this output (that is, I don't want anything to be printed)?

6 Answers 6

32

Just add > NUL: to the end of your command.

4
  • 3
    What is the colon for? Oct 20, 2015 at 23:01
  • 6
    @PeterMortensen: In DOS and Windows console, reserved device names such as NUL can be followed by an optional colon. As far as I know, it performs no actual function, but serves as a visual reminder that it's a device and parallels the use of a colon after a drive letter. Oct 20, 2015 at 23:14
  • 1
    To disable the standard output while letting it still display errors, add 1>NUL instead. (or maybe 1>NUL: if you like the trailing colon) Feb 16, 2023 at 11:40
  • Related annoying tidbit: apart from NUL, the ancient DOS-originated names CON, LPT, PRN and a whole bunch of others (mostly variants, including all of them with any extensions appended! :-o ) are still reserved in Windows (11, too), so to this day you can't just call e.g. a project subdir of external resources aux...
    – Sz.
    Feb 20, 2023 at 14:22
39

You can use the -bs command to control where output goes. To stop anything but error output, I would add -bso0 -bsp0.

2
12

It is highly recommended to view status messages in the process. To avoid long messages, display only confirmations:

...\right_path\7z a output_file_name.zip file_to_be_compressed | findstr /b /r /c:"\<Everything is Ok" /c:"\<Scanning" /c:"\<Creating archive"
3
  • Thanks for the findstr solution! It looks like you can somewhat shorten that call by either omitting /b or both the \r and the \< inside the search strings. I'd go with findstr /b /c:"Everything is Ok" /c:"Scanning" /c:"Creating archive" since you don't need regular expressions (the /r option) here - /b already searches only at the beginning of strings.
    – Oliver
    Feb 23, 2013 at 9:43
  • if you want to use status messages to check whether the command succeeded it is better to use return codes (0 for success and others which detail what failed). It is easier in a script to make decisions based on these values than on messages.
    – WoJ
    Mar 26, 2015 at 8:29
  • 1
    Great answer. I went with ... | findstr /v /b /c:"Compressing " to get rid of the file listing but keep the other status messages. May 11, 2016 at 19:34
5

Improving Bruno Dermario answer, I wanted to also report errors and be able to check them manually.

...\right_path\7z a output_file_name.zip file_to_be_compressed > 7z_log.txt
type 7z_log.txt | findstr /b /c:"Everything is Ok" /c:"Scanning" /c:"Creating archive" /c:"Error"
echo.
echo (In case of Error check 7z_log.txt)
echo.
3

In case PowerShell is an option or somebody could use it, here's what I did, based on the idea of the findstr answer.

& $sevenZipBin a "$archiveFile" * | where {
    $_ -notmatch "^7-Zip " -and `
    $_ -notmatch "^Scanning$" -and `
    $_ -notmatch "^Creating archive " -and `
    $_ -notmatch "^\s*$" -and `
    $_ -notmatch "^Compressing "
}
if (-not $?)
{
    # Show some error message and possibly exit
}

In normal operation, this leaves only the "Everything is Ok" line. Should anything unusual be printed, it remains visible (except for empty lines as they appear so often in regular output).

This is tested for 7z format output. Other archive formats may produce other messages than "Compressing". Extracting will likely also produce different messages. But you can easily adapt the filter to your needs.

A more complex idea would be to redirect all output to a buffer and only print it in case the command returns an error exit code. This is a method that works with all commands that allow redirecting and provide an accurate error exit code.

1
  • If you're using Powershell you could also just pipe the output to null by appending | Out-Null to your statement. Mar 29, 2022 at 12:36
1

Sharing my findstr solution:

%ZIP% a -tzip %FILE% %Folder% | findstr /I "archive everything"

So the original 14-lines output:


7-Zip 18.01 (x64) : Copyright (c) 1999-2018 Igor Pavlov : 2018-01-28

Scanning the drive:
4 folders, 13 files, 88957 bytes (87 KiB)

Creating archive: Releases\Archive.zip

Add new data to archive: 4 folders, 13 files, 88957 bytes (87 KiB)


Files read from disk: 13
Archive size: 33913 bytes (34 KiB)
Everything is Ok

shrink to the 4-lines:

Creating archive: Releases\Archive.zip
Add new data to archive: 4 folders, 13 files, 88957 bytes (87 KiB)
Archive size: 33912 bytes (34 KiB)
Everything is Ok

it shrinks only the sOut, warnings and errors goes to the sErr, so you still will see them

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