Slow for loop iteration in batch file - powershell

Question

So I'm making a batch script and I need to run a powershell command inside a for but it's running really slow, I don't know how to make it more efficient, I'm very new in this stuff. Here's part of my code:
for /f "tokens=*" %%G in (myfile.txt) do (
powershell -command '%%G' -replace ',+', ' ' >> newfile.txt
)

Answer 1

Since you say you are new to this. It's really important you get some ramp up on the topic. Using either all the free stuff Microsoft offers (Microsoft Virtual Academy or MS Channel9 or TechNet Virtual Labs or labsondemand), or youtube or at minimum review the help files first. There are lots of free eBooks as well and step by step blogs.
As the others have said, why not just do this in PS directly, to read and process the file. Though you don't have to, you can call a .ps1 from a .bat/.cmd/.vbs, etc., but you don't have to use it to process what PS can do.
# Giving a target file to be modified
# Check what is in the file
# Note: I am using Get-Content here, but if you have a .csv, then use the *csv* cmdlets
Get-Content -Path 'd:\temp\myfile.txt'
# Results
LIC,+CLIENT
12345,+Client1
54321,+Client2
34251,+Client3
# Test new file path
Test-Path -Path 'd:\temp\newfile.txt'
# Results
False
# Decide what to replace, code the replace
# and see what the new file content will look like when replaced
Get-Content -Path 'd:\temp\myfile.txt' |
ForEach{$_ -replace '\,\+',' '}
# Results
LIC CLIENT
12345 Client1
54321 Client2
34251 Client3
# Modify to send to a new file.
Get-Content -Path 'd:\temp\myfile.txt' |
ForEach{
$_ -replace '\,\+',' ' |
Out-File -FilePath 'D:\Temp\newfile.txt' -Append
}
# Results
Test-Path -Path 'd:\temp\newfile.txt'
True
Get-Content -Path 'd:\temp\newfile.txt'
# Results, should be the same as screen output.
LIC CLIENT
12345 Client1
54321 Client2
34251 Client3

Answer 2

Since you mentioned in your comment that you were trying to do it all in a batch script here is the basic syntax for string replacement. You have to first assign the FOR variable to an environmental variable before you can do any string replacement. You would also need to enable delayed expansion because you are manipulating a variable inside a parentheses code block.
#echo off
setlocal enabledelayedexpansion
(for /f "delims=" %%G in (myfile.txt) do (
set "line=%%G"
echo !line:+= !
)
)>newfile.txt
You could also do this without delayed expansion by using CALL ECHO
#echo off
(for /f "delims=" %%G in (myfile.txt) do (
set "line=%%G"
CALL echo %%line:+= %%
)
)>newfile.txt