Question

Let’s say I have a file containing the following:

set_t lorem = "168"
set_t ipsum = "913"
set_t dolor = "294"
...

Really, what is set, I cannot know in the batch file I’m working in. the only thing I know for sure is the “set_t lorem” part.

But I need to replace whatever value it has (168 i.e in set_t lorem) with i.e 100.

How would I do this in a batch file?
Vbs or external binaries is OK; though not to many dependencies would be great. It needs to be mass-distributed.

Answer 1

Here’s a VBScript solution:

Option Explicit

Const ForReading = 1
Const ForWriting = 2

Dim filename, prefix, newvalue, fso, file, str, line
Set fso = CreateObject("Scripting.FileSystemObject")

' Read and validate the parameters
If Not WScript.Arguments.Count = 3 Then
  Wscript.Echo "Syntax: PatchData FileName Prefix NewValue"
  Wscript.Quit 1
End If
filename = Wscript.Arguments(0)
prefix = Wscript.Arguments(1)
newvalue = Wscript.Arguments(2)
If Not fso.FileExists(filename) Then
  Wscript.Echo "Filename does not exists " & filename
  Wscript.Quit 1
End If

' Read the file 1 line at a time into a string, patching as we go
str = ""
Set file = fso.OpenTextFile(filename, ForReading)
While not file.AtEndOfStream
  line = file.ReadLine
  If Left(line, Len(prefix)) = prefix Then
    line = prefix & " = """ & newvalue & """"
  End If
  str = str & line & vbCrLf
Wend
Set file = Nothing

' Write the patched string back to the file
Set file = fso.OpenTextFile(filename, ForWriting)
file.Write str
Set file = Nothing