Remove a portion of String after certain value

Question

I am using below mentioned code for finding a string in a file(Constants.TcGVL), assign my desired value(%select%) to it and copy to a new location:

Call :ValueSubstitude "%root%\LeafSpring\Constants.TcGVL"  "%root%\LeafSpring\GVLs\Constants.TcGVL" "%select%"

:ValueSubstitude
@echo off
SETLOCAL ENABLEEXTENSIONS DISABLEDELAYEDEXPANSION
Set "Tag1=nNrOfInstances : UINT := " 
Set "Tag2=%~3"
for /f "delims=" %%a in (%~1) do ( 
Set "str=%%a"
setLocal EnableDelayedExpansion
Set str=!str:%Tag1%=%Tag1%%Tag2%!
echo !str!>>"%~2"
ENDLOCAL
)
Exit /B 0

Original file has string like this: nNrOfInstances : UINT := 3;

Now my %select% value could be 1, 2 ,3...and I want to replace '3' in above line with my desired number but the output I am getting is wrong.

The output looks like this:

=nNrOfInstances : UINT := 1= 3;

It has a space and equal sign at start of line and = 3 at the end. It has my desire number in it which is 1 but also the earlier value = 3 which should not be there.

Kindly assist me getting the right output or let me know what am I doing wrong here. Thank you.

Answer 1

@ECHO OFF
SETLOCAL

SET "tag2=2"
Set "Tag1=nNrOfInstances : UINT := " 
for /f "delims=" %%e in (q77984148.txt) do (
 ECHO %%e|FINDSTR /b /L /c:"%tag1%" >NUL
 IF ERRORLEVEL 1 (ECHO %%e) ELSE (
 ECHO %tag1%%tag2%;)
)

I used a file named q77984148.txt containing your data and some junk data for my testing.

The replacement processing uses findstr to see whether the line read (in %%e) begins with (/b) the literal string (/L) constant (/c:"this string"), and suppressing the output (>nul). This sets errorlevel to 0 if found and 1 if not.

If the resultant errorlevel is 1 or greater, simply echo the line, else (the string was found) so reconstruct the line (including the terminal ; which appears to have become lost in your narrative)

Note that the construction

(
for....do.(
 ....
)
)>filename

will recreate filename with the contents of (whatever the for loop outputs).

Naturally >>filename will append this data to an existing file filename or create that file if it doesn't already exist