PowerShell: read lines from text file, construct source and destination file names, then copy files

Question

I'm a PowerShell novice, and I'd love to be able to script this. I have a text file where each line is part of a file name without the path or extension. I'd like a one-liner that loops through each line of the file (with a gc - Get-Content, right?), takes the content of the line, constructs the source path (the network drive and extension are static), constructs a destination path, and then copies each file. My file content is like this:

12345678
98765432
32145698
12365782

And my source folder is a UNC path like this:

\\server\share

And my destination folder is:

c:\temp\files

I would like to do the equivalent of this DOS command, using $_ as the text from each line of the file:

copy \\server\share\$_.ext c:\temp\files\$_.ext

I'm pretty sure I can use gc and $_ to access each line of the file, and that I need to use cp to copy the files, but I'm having trouble constructing the source and destination file names.

Answer 1

Try the following

gc theFileName | 
  %{ "{0}.ext" -f $_ } |
  %{ copy "\\server\share\$_" "c:\temp\files\$_" }

It can actually be done on one line but it looks better formmated as multiple lines for this answer :)

Answer 2

Copy-Item can take a script block directly in this case so the Foreach-Object stages are unnecessary:

gc theFileName | cpi -l {"\\server\share\$_.exe"} c:\temp\files -whatif

Remove the -WhatIf parameter once you're satisfied it works. The -l is short for -LiteralPath which helps PowerShell determine which parameterset is in use. Also better to use literal path here so that wildcard characters don't get globbed (unless you want that - if so then use -path).

Essentially pipeline bound parameters can be specified via scriptblocks and PowerShell will attempt to resolve the result of the scriptblock to the type expected by the pipeline bound parameter.