in reply to Perl and 7zip and backticks

The status information comes out via stderr, so you'll need to redirect that in order to capture it.

Try:

open PIPE, '-|', '"\Program Files\7-Zip\7z.exe" a -r -mx0 -tzip e:\the
+Zip.zip 2>&1' or die $@;;

while( <PIPE> ) {
    # do something with the status output here
}

[download]

Update: Here's the test I ran of my suggestion:


Perl> open PIPE, '-|', '"\Program Files\7-Zip\7z.exe" e -so e:\UnxUtil
+sSrc.zip 2>&1 1>nul' or die $@;;

Perl> print <PIPE>;;

 7-Zip [64] 9.20  Copyright (c) 1999-2010 Igor Pavlov  2010-11-18

 Processing archive: e:\UnxUtilsSrc.zip

 Extracting  unxutils
 Extracting  unxutils\CVS
 Extracting  unxutils\CVS\Root
 Extracting  unxutils\CVS\Repository
 Extracting  unxutils\CVS\Entries
 Extracting  unxutils\Downhill
 Extracting  unxutils\Downhill\CVS
 Extracting  unxutils\Downhill\CVS\Root
 Extracting  unxutils\Downhill\CVS\Repository
 Extracting  unxutils\Downhill\CVS\Entries
 Extracting  unxutils\Downhill\DOC
 Extracting  unxutils\Downhill\DOC\CVS
 Extracting  unxutils\Downhill\DOC\CVS\Root
 Extracting  unxutils\Downhill\DOC\CVS\Repository
...
 Extracting  unxutils\zsh\Src\zle_utils.c
 Extracting  unxutils\zsh\Src\zle_utils.pro
 Extracting  unxutils\zsh\Src\zle_vi.c
 Extracting  unxutils\zsh\Src\zle_vi.pro
 Extracting  unxutils\zsh\Src\zle_word.c
 Extracting  unxutils\zsh\Src\zle_word.pro
 Extracting  unxutils\zsh\Src\zsh.exe
 Extracting  unxutils\zsh\Src\zsh.h
 Extracting  unxutils\zsh\Src\zsh.map
 Extracting  unxutils\zsh\Src\ztype.h
 Extracting  unxutils\zsh\Src\_exrc

 Everything is Ok

 Folders: 640
 Files: 10528
 Size:       108861113
 Compressed: 38592955

[download]

I used -so & >nul to avoid the files actually being created, but omit those and they will.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
In the absence of evidence, opinion is indistinguishable from prejudice.

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Re^2: Perl and 7zip and backticks
by Anonymous Monk on Feb 27, 2016 at 22:43 UTC
    Hi Browser. Thanks for your reply, interesting if 7zip updates its progress via STDERR. I tried your example and 7zip seemed to update more often but in blocks of output not each line as it was being zipped (talking large GB) files here so it's easy to see it update per item. I'll fiddle around with your example more. Cheers
[reply]
      but in blocks of output not each line as it was being zipped

      Unfortunately that is par for the course with pipes; they have their own buffer. Indeed, that pretty much defines what a pipe is: a piece of shared memory buffer space.

      The pipe will accumulate output from the writer until the buffer (often 4K) fills, and only then does it start to satisfy the reader. In most cases that is a good thing as it prevents the processes giving up time-slices and switching back and forth in lockstep.

      Other than setting up the pipe yourself -- a messy procedure easy to get wrong -- and using the barely documented ioctl calls to specify the buffer size(s), I don't know any way of avoiding that.

      With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)
      In the absence of evidence, opinion is indistinguishable from prejudice.
[reply]

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