Batch modifying directory with Powershell - powershell

Question

I need to update directory in many txt files
Input files:
1.txt
using c:\data\1.dta
its own data
2.txt
using c:\data\2.dta
its own data
3.txt
using c:\data\3.dta
its own data
Expected Output files:
1.txt
using C:\Data\Subfile\1.dta
its own data
2.txt
using C:\Data\Subfile\2.dta
its own data
3.txt
using C:\Data\Subfile\3.dta
its own data
I've tried -replace but the results are strange: either all files have the same result or have all new directories (sell bellow)
I want to update the oldpath into the newpath in all files. The code is as following:
$pathway='C:Data\Subfile\*.txt'
$oldpath='c:\\data\\'
$newpath='C:\Data\Subfile\'
$content=Get-Content -path $pathway
Method 1:
$newline=((Get-Content -path $pathway -TotalCount 1) -replace $oldpath,$newpath)
$content[0]= $newline
This method will include all updated directories in every file:
Wrong output:
1.txt
using C:\Data\Subfile\1.txt
using C:\Data\Subfile\2.txt
using C:\Data\Subfile\3.txt
its own data
2.txt
using C:\Data\Subfile\1.txt
using C:\Data\Subfile\2.txt
using C:\Data\Subfile\3.txt
its own data
Method 2:
$content[0]=$content[0]-replace $oldpath,$newpath
This method will cause all file has the same new directory:
Wrong output:
1.txt
using C:\Data\Subfile\1.txt
its own data
2.txt
using C:\Data\Subfile\1.txt
its own data
3.txt
using C:\Data\Subfile\1.txt
its own data
$content | Set-Content -Path $pathway
Can someone help me with that? I want each file has its corresponding new directory. For 1.txt I want C:\Data\Subfile\1.txt, for 2.txt I want C:\Data\Subfile\2.txt etc.
Thanks a lot!

Answer 1

I'm a bit unclear on what you want the final content to be. Is it using C:\Data\Subfile\1.txt or using C:\Data\Subfile\1.dta? I think you are asking for the following but if not let me know. You may run into speed / performance issues depending on how large your files are.
If these are your input files with their content:
C:\data\Subfile\1.txt
using c:\data\1.dta
its own data...
C:\data\Subfile\2.txt
using c:\data\2.dta
its own data...
C:\data\Subfile\3.txt
using c:\data\3.dta
its own data...
then this:
Get-ChildItem c:\data\Subfile\*.txt | Foreach-Object{
#Read in all content lines and replace c:\data\ with c:\data\subfile
$content = Get-Content $_.FullName | %{$_ -replace 'c:\\Data\\', 'c:\Data\Subfile\' }
#write the new data to file
$content | Set-Content $_.FullName
}
This results in the following:
C:\data\Subfile\1.txt
using c:\Data\Subfile\1.dta
its own data...
C:\data\Subfile\2.txt
using c:\Data\Subfile\2.dta
its own data...
C:\data\Subfile\3.txt
using c:\Data\Subfile\3.dta
its own data...

Answer 2

With lookarounds you can precisely define where to insert text without repeating the search pattern.
foreach ($File in Get-ChildItem 'C:\Data\Subfile\*.txt'){
(Get-Content $File -raw) -replace "(?<=C:\\data\\)(?=\d\.dta)","Subfile\" |
Set-Content $File
}
"(?<=C:\\data\\) is a positive lookbehind zero length assertion,
(?=\d\.dta) is a positive lookahead zero length assertion,
the replacement text is inserted in between these two.
this is more secure than other approaches as it is repeatable without inserting Subfile\ again.

Answer 3

here is a way to do the job. [grin] what it does ...
between the #region/#endregion markers is just to make the files to work with
reads the list of files
iterates thru that list
loads the content of each one
replaces the old dir with the new one
finally writes out the new content
here's the code ...
#region - Make files to work with
$Null = New-Item -Path "$env:TEMP\TestFiles" -ItemType Directory -ErrorAction SilentlyContinue
$1stFileName = "$env:TEMP\TestFiles\1.txt"
$1stFileContent = #'
using c:\data\1.dta
its own data
'# -split [System.Environment]::NewLine |
Set-Content -LiteralPath $1stFileName
$2ndFileName = "$env:TEMP\TestFiles\2.txt"
$2ndFileContent = #'
using c:\data\2.dta
its own data
'# -split [System.Environment]::NewLine |
Set-Content -LiteralPath $2ndFileName
$3rdFileName = "$env:TEMP\TestFiles\3.txt"
#'
using c:\data\3.dta
its own data
'# -split [System.Environment]::NewLine |
Set-Content -LiteralPath $3rdFileName
#endregion - Make files to work with
$OldDir = 'c:\data'
$NewDir = 'c:\data\SubDir'
$SourceDir = "$env:TEMP\TestFiles"
$FileList = Get-ChildItem -LiteralPath $SourceDir -Filter '*.txt' -File
foreach ($FL_Item in $FileList)
{
$NewContent = Get-Content -LiteralPath $FL_Item.FullName |
ForEach-Object {
$_.Replace($OldDir, $NewDir)
}
$NewContent |
Set-Content -LiteralPath $FL_Item.FullName
}
content of file 1.txt before & after the script runs ...
# before ...
using c:\data\1.dta
its own data
# after ...
using c:\data\SubDir\1.dta
its own data