CMD or Powershell command to combine (merge) corresponding lines from two files

Question

Is it possible using CMD and Powershell to combine 2 files into 1 file like this:

file1-line1 tab file2-line1
file1-line2 tab file2-line2
file1-line3 tab file2-li         


        

Answer 1

Probably the simplest solution is to use a Windows port of the Linux paste utility (e.g. paste.exe from the UnxUtils):

paste C:\path\to\file1.txt C:\path\to\file2.txt

From the man page:

DESCRIPTION

Write lines consisting of the sequentially corresponding lines from each FILE, separated by TABs, to standard output.

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For a PowerShell(ish) solution, I'd use two stream readers:

$sr1 = New-Object IO.StreamReader 'C:\path\to\file1.txt'
$sr2 = New-Object IO.StreamReader 'C:\path\to\file2.txt'

while ($sr1.Peek() -ge 0 -or $sr2.Peek() -ge 0) {
  if ($sr1.Peek() -ge 0) { $txt1 = $sr1.ReadLine() } else { $txt1 = '' }
  if ($sr2.Peek() -ge 0) { $txt2 = $sr2.ReadLine() } else { $txt2 = '' }

  "{0}`t{1}" -f $txt1, $txt2
}

This avoids having to read the two files entirely into memory before merging them, which bears the risk of memory exhaustion for large files.