Concatenate dataset in powershell - windows

Question

I have a problem in concatenating compressed files and extracting them in Windows Powershell environment.
My machine is Windows 10 and I have compressed dataset dataset as follow:
lr_v1_paa
lr_v1_pab
lr_v1_pac
I concatenated the above files into lr_v1.tar using Windows powershell command:
cat lr_v1_pa* > lr_v1.tar
and ran tar -xf lr_v1.tar to extract concatenated files. But, I got the following error message:
tar.exe: Error opening archive: Unrecognized archive format
Why tar.exe in powershell cannot recognize .tar format?

Answer 1

As you've found, cat lrs2_v1_parta* > lrs2_v1.tar doesn't work well with binary files in PowerShell.
To concatenate multiple binary files into one target file, here's how I would do it:
# discover input files
$inputFiles = Get-Item lrs2_v1_parta*
# create new target file
$destFile = New-Item -Name lrs2_v1.tar -ItemType File
# open writable file stream to target file
$outStream = $destFile.OpenWrite()
try{
foreach($file in $inputFiles){
# open file stream for reading from input file
$inStream = $file.OpenRead()
try {
# copy input file stream to destination file stream
$inStream.CopyTo($outStream) |Out-Null
}
finally {
# clean up input file handle
$inStream.Dispose()
}
}
}
finally {
# clean up output file stream
$outStream.Dispose()
}
You should expect to find a non-corrupt lrs2_v1.tar in the current folder after this operation :)