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Solve : .bat file making search and replace in text file?

Answer»

Does anyone know how to write a .bat that looks for a string in a text file and replaces it with something else?
You need to read the help for command SET:

Quote

SET /?
...
Environment variable substitution has been enhanced as follows:

%VAR:str1=str2%

would expand the VAR environment variable, substituting each occurrence of "str1" in the expanded result with "str2". "str2" can be the empty string to effectively delete all occurrences of "str1" from the expanded output. "str1" can begin with an asterisk, in which case it will match everything from the beginning of the expanded output to the first occurrence of the remaining portion of str1.
...
THANKS!

I have tried this but it does not run as I expected.

I have the file test.txt containing the single word "Charlie".

the bat script looks as follows:

set var=
for /f "tokens=*" %%A in ('type test.txt') do set myVar=%%A

echo %myvar%

set str1=Charlie
set str2=Bob

%myVar:str1=str2%

echo %myvar%

_______________________________________ ______________________
Now when I run this it returns/echos:

C:\Transfer>set var=

C:\Transfer>for /F "tokens=*" %A in ('type test.txt') do set myVar=%A

C:\Transfer>set myVar=Charlie

C:\Transfer>echo Charlie
Charlie

C:\Transfer>set str1=Charlie

C:\Transfer>set str2=Bob

C:\Transfer>Charlie
'Charlie' is not recognized as an internal or external command,
operable program or batch file.

C:\Transfer>echo Charlie
Charlie
_______________________________________ ___

so the %myVar:str1=str2% try to execute the content of str1??????

What did I miss???The sentence

%myVar:str1=str2%

return a new variable where it's been replaced the word "str1" for "str2".
You would need:

set myVar=%myVar:str1=str2%

But in 'myVar' there isn't the word "str1". I have tried to put:

set myVar=%myVar:%str1%=%str2%%

but it seems that it doesn't admit variables within variables.

If you run a subshell cmd /v: on, the next work:

Code: [Select]@echo off
for /f "tokens=*" %%A in (test.txt) do set myVar=%%A

echo %myvar%

set str1=Charlie
set str2=Bob

set myvar=!myVar:%str1%=%str2%!

echo [ %myvar% ]Batch coding was never meant to do much more than run programs sequentially. Using batch as a programming language is like using a SPOON to dig the Panama Canal. Yes, it can be done, but it's not the best tool for the job.

Code: [Select]Const ForReading = 1
Const ForWriting = 2
Const FileIn = "c:\test.txt"
Const FileOut = "c:\test.txt" '<== Change to prevent overwrite of original file

Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile(FileIn, ForReading)

strText = objFile.ReadAll
objFile.Close
strNewText = Replace(strText, "Charlie ", "Bob ")

Set objFile = objFSO.OpenTextFile(FileOut, ForWriting)
objFile.WriteLine strNewText
objFile.Close

Save the script with a vbs extension and run from the command line as: cscript scriptname.vbs. As WRITTEN, the script will overwrite the original file. You can modify this by changing the FileOut parameter.

Just my 2¢ worth. 8-)Thanks Carlos! You are a Star!!!
That works briliant!


This really helped me out.
Ah Yes.

I have THOUGHT of looking in to vbs just have not had time yet.
I might just do that in a hurry now though.

Thanks.Since this is DOS FORUM here is a possible DOS solution ...

At http://dostips.cmdtips.com/DtCodeBatchFiles.php you can find a section about [highlight]String Substitution[/highlight]. It shows a batch file that replaces text in a text file.

The main task is being done by a few lines of code similar to this:

Code: [Select]SETLOCAL ENABLEEXTENSIONS
SETLOCAL ENABLEDELAYEDEXPANSION

REM -- Parse each line
REM -- Trick, add line numbers using find command, to preserve empty lines

set src=<source file>
set str1=<old string>
set str2=<new string>

for /f "tokens=1,* delims=]" %%a in ('"find /n /v "@#$PreserveEmptyLines$#@" "%src%""') do (
if "%%b"=="" (
echo.
) else (
set line=%%b
call echo.!line:%str1%=%str2%!
)
)
Due to the nature of the FOR command and Delayed Expansion, some restrictions for the content of the text file apply.

Hope this information is useful for somebody


I just figured out that find /v "" filename.txt returns all lines of a file, so the funny @#$PreserveEmptyLines$#@ is not needed. The for command can be written like this:

for /f "tokens=1,* delims=]" %%a in ('"find /n /v "" "%src%""') do (...


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