CODEWITHSUNDEEP
powershell
lonelydev101
lonelydev101

Reputation: 1901

Remove spaces and blank lines from txt files

I have a script which is not working:

$files = Get-ChildItem "C:\test\"
for ($i=0; $i -lt $files.Count; $i++) {
  $outfile = $files[$i].FullName + "out" 
  Get-Content $files[$i].FullName | ? {$_.Trim() -ne "" } | Set-Content $files[$i].FullName
}

Error is:

Set-Content : The process cannot access the file 'C:\test\ADMINISTRATOR.txt'
because it is being use
At D:\skriptablank.ps1:4 char:63
+     Get-Content $files[$i].FullName | ? {$_.Trim() -ne "" } | Set-Content $files ...
+                                                               ~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Set-Content], IOException
    + FullyQualifiedErrorId : System.IO.IOException,Microsoft.PowerShell.Commands.SetContentCommand

What do you think, where I am doing it wrong?

Upvotes: 0

Views: 1830

Answers (1)

Ansgar Wiechers
Ansgar Wiechers

Reputation: 200193

You're using Get-Content and Set-Content on the same file in a pipeline:

Get-Content $files[$i].FullName | ... | Set-Content $files[$i].FullName

When you do this, the file is usually still being read from when Set-Content starts writing to it, thus causing the error you observed. You need to either finish reading before you start writing:

(Get-Content $files[$i].FullName) | ... | Set-Content $files[$i].FullName

or write to a temporary file first and then replace the original file with the temp file:

Get-Content $files[$i].FullName | ... | Set-Content "$env:TEMP\foo.txt"
Move-Item "$env:TEMP\foo.txt" $files[$i].FullName -Force

For small files you normally want to use the first approach, because reading the entire file into memory instead of reading it line-by-line is faster and easier to handle.

For large files you normally want to use the second approach in order to avoid memory exhaustion. Make sure to create the temp file on the same filesystem as the file you want to replace, so you don't have to copy the entire data again when moving the temp file (move operations within a filesystem/volume just need to change the reference to the file, which is significantly faster than shifting the file's content).

Upvotes: 2

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