batch-file File Handling in batch files Editing Nth Line of a File
Example
Batch file does not come with a built-in method for replacing nth line of a file except replace and append(> and >>). Using for loops, we can emulate this kind of function.
@echo off
set file=new2.txt
call :replaceLine "%file%" 3 "stringResult"
type "%file%"
pause
exit /b
:replaceLine <fileName> <changeLine> <stringResult>
setlocal enableDelayedExpansion
set /a lineCount=%~2-1
for /f %%G in (%~1) do (
if !lineCount! equ 0 pause & goto :changeLine
echo %%G>>temp.txt
set /a lineCount-=1
)
:changeLine
echo %~3>>temp.txt
for /f "skip=%~2" %%G in (%~1) do (
echo %%G>>temp.txt
)
type temp.txt>%~1
del /f /q temp.txt
endlocal
exit /b
-
The main script calls the function
replaceLine, with the filename/ which line to change/ and the string to replace. -
Function receives the input
- It loops through all the lines and
echothem to a temporary file before the replacement line - It
echoes the replacement line to the file - It continues to output to rest of the file
- It copies the temporary file to the original file
- And removes the temporary file.
- It loops through all the lines and
-
The main script gets the control back, and
typethe result.
