powershell7zip

"Unknown Switch" error when using 7-zip in PowerShell script to archive file names that start with a `-`


I have a series of files in a folder that contain large log files

-20180907 1229 debug.log
-20180907 1229 system.log

I want to write a PowerShell script to archive them down in size. Here's my script:

dir *.log | % {
    $archive = '"' + $_.Name + '.7z"'
    $archive
    $source = '"' + $_.Name + '"'
    $source
    &"C:\Program Files\7-Zip\7z.exe" -mx9 a -t7z $archive $source -WhatIf
}

When I run it, however, I get the following output:

"-20180907 1229 debug.log.7z"
"-20180907 1229 debug.log"
7z.exe : 
At C:\Users\User\Temporary\Test 7z\archive-logs.ps1:6 char:5
+     &"C:\Program Files\7-Zip\7z.exe" -mx9 a -t7z $archive $source
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

Command Line Error:
Unknown switch:
-20180907 1229 debug.log.7z
"-20180907 1229 system.log.7z"
"-20180907 1229 system.log"
7z.exe : 
At C:\Users\User\Temporary\Test 7z\archive-logs.ps1:6 char:5
+     &"C:\Program Files\7-Zip\7z.exe" -mx9 a -t7z $archive $source
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

Command Line Error:
Unknown switch:
-20180907 1229 system.log.7z

Even though I am wrapping the file name in double quotes it appears as 7-Zip is ignoring the double quotes.

Any ideas?


I tried this variant (wrapping the file names in single quotes):

dir *.log | % {
    $archive = "'" + $_.Name + ".7z'"
    $archive
    $source = "'" + $_.Name + "'"
    $source
    &"C:\Program Files\7-Zip\7z.exe" -mx9 a -t7z $archive $source
}

And this time I got this output:

'-20180907 1229 debug.log.7z'
'-20180907 1229 debug.log'

7-Zip 18.05 (x64) : Copyright (c) 1999-2018 Igor Pavlov : 2018-04-30

Open archive: '-20180907 1229 debug.log.7z'
--
Path = '-20180907 1229 debug.log.7z'
Type = 7z
Physical Size = 32
Headers Size = 0
Solid = -
Blocks = 0

Scanning the drive:
7z.exe : 
At C:\Users\User\Temporary\Test 7z\archive-logs-B.ps1:6 char:5
+     &"C:\Program Files\7-Zip\7z.exe" -mx9 a -t7z $archive $source
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:String) [], RemoteException
    + FullyQualifiedErrorId : NativeCommandError

WARNING: The system cannot find the file specified.
'-20180907 1229 debug.log'
0 files, 0 bytes

Updating archive: '-20180907 1229 debug.log.7z'

Add new data to archive: 0 files, 0 bytes


Files read from disk: 0
Archive size: 32 bytes (1 KiB)

Scan WARNINGS for files and folders:

'-20180907 1229 debug.log' : The system cannot find the file specified.
----------------
Scan WARNINGS: 1

It's created files like '-20180907 1229 debug.log.7z', but with no content.


Solution

  • Try this:

     $executable = "C:\Program Files\7-Zip\7z.exe"
    
     dir *.log | % {
        $archive = "$($_.Name).7z"
        $archive
        $source = $_.Name
        $source 
        $oneliner = "a",".\$($archive)",".\$($source)", "-mx4"
        & $executable @oneliner
    }