• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 4697
  • Last Modified:

PowerShell script to find a string and delete all lines in a text file that do not have it

I am wondering if it's possible to create a powershell script to do the following:

Find a value of lets say 123 in a text file

The value of 123 is in Line 2 of the text file but not Line 1 or 3.

I want it to delete line 1 and 3 but save line 2.

This would need to be done for thousands of lines.

Is this possible? Powershell or DOS, VB?

thanks in advance
0
awgit
Asked:
awgit
  • 2
1 Solution
 
chrismerrittCommented:
Try this, but please test it first. i.e backup the file you are testing against.

Will overwrite the specified file content with any lines that contain the word in the $match variable. i.e. it will only keep lines that match your requirements, all other lines will be removed.

#Customise Vars
$SourceFile = "C:\TEMP\test.txt"
$Match = "123"

(Get-Content $SourceFile) | % {if ($_ -match $Match){$_}} | Set-Content $SourceFile

Open in new window

0
 
awgitAuthor Commented:
That worked!

As I was testing myself I just found another command that also worked. Instead of modifying the original file it exports out the results to another file

This is the command that does that:
get-childitem C:\scripts\source.txt | select-string -pattern 123 | foreach {$_.line} > C:\scripts\123.txt
0
 
chrismerrittCommented:
No problem, you could save to another file by modifying my code as follows as well:

#Customise Vars
$SourceFile = "C:\TEMP\test.txt"
$DestinationFile = "C:\TEMP\new.txt"
$Match = "123"

(Get-Content $SourceFile) | % {if ($_ -match $Match){$_}} | Set-Content $DestinationFile

Open in new window

0

Featured Post

Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

  • 2
Tackle projects and never again get stuck behind a technical roadblock.
Join Now