Extracting a 7-Zip file “silently” - command line option

Tag: 7zip Author: cedar1010 Date: 2010-09-06

I want to extract a 7-Zip archive in a Python script. It works fine except that it spits out the extraction details (which is huge in my case).

Is there a way to avoid this verbose information while extracting? I did not find any "silent" command line option to 7z.exe.

My command is

7z.exe -o some_dir x some_archive.7z

Best Answer

One possibility would be to spawn the child process with popen, so its output will come back to the parent to be processed/displayed (if desired) or else completely ignored (create your popen object with stdout=PIPE and stderr=PIPE to be able to retrieve the output from the child).

comments:

Thanks. That helped. I tried subprocess.Popen. But then my parent process is done before the child returns. I would like to check the returncode of the child before continuing. Am going through docs but let me know if you know how to stall (especially with stdout=PIPE) off hand.
Got it. popen.communicate does it
What's the equivalent solution on Windows? ...

Other Answer1

I just came across this when searching for the same, but I solved it myself! Assuming the command is processed with Windows / DOS, a simpler solution is to change your command to:

7z.exe -o some_dir x some_archive.7z > nul

That is, direct the output to a null file rather than the screen.

Or you could pipe the output to the DOS "find" command to only output specific data, that is,

7z.exe -o some_dir x some_archive.7z | FIND "ing archive"

This would just result in the following output.

Creating archive some_archive.7z

or

Updating archive some_archive.7z**


My final solution was to change the command to

... some_archive.7z | FIND /V "ing  "

Note double space after 'ing'. This resulted in the following output.

7-Zip 9.20  Copyright (c) 1999-2010 Igor Pavlov  2010-11-18

Scanning

Updating some_archive.7z


Everything is Ok

This removes the individual file processing, but produces a summary of the overall operation, regardless of the operation type.

comments:

nice solution. if you don't like Igor like I do, you can remove hom too with: ... some_archive.7z | FIND /V "ing " | FIND /V "Igor Pavlov"

Other Answer2

Like they said, to hide most of the screen-filling messages you could use ... some_archive.7z | FIND /V "Compressing" but that "FIND" would also remove the error messages that had that word. You would not be warned. That "FIND" also may have to be changed because of a newer 7-zip version.

7-zip has a forced verbose output, no silence mode, mixes stderr and stdout(*), doesn't save Unix permissions, etc. Those anti-standards behaviors together put "7-zip" in a bad place when being compared to "tar+bzip2" or "zip", for example.

(*) "Upstream (Igor Pavlov) does not want to make different outputs for messages, even though he's been asked several times to do so :(" http://us.generation-nt.com/answer/bug-346463-p7zip-stdout-stderr-help-166693561.html - "Igor Pavlov does not want to change this behaviour" http://sourceforge.net/tracker/?func=detail&aid=1075294&group_id=111810&atid=660493

Other Answer3

7zip does not have an explicit "quiet" or "silent" mode for command line extraction.

One possibility would be to spawn the child process with popen, so its output will come back to the parent to be processed/displayed (if desired) or else completely ignored (create your popen object with stdout=PIPE and stderr=PIPE to be able to retrieve the output from the child).

Otherwise Try doing this:

%COMSPEC% /c "%ProgramFiles%\7-Zip\7z.exe" ...

Other Answer4

The | FIND is a good alternative to show what happened without displaying insignificant text.