This is the simplest way to do this that I could come up with. It takes a String and searches for it in a file, then replaces the entire line that contains the string. It won't only replace parts of a line, which can be done with a bit more effort.
@echo off
:: file containing string to replace
set file=test.txt
:: string to replace in file
set searchString=line 4
:: string to write to file
set repString=line 4 edited
setLocal enableDelayedExpansion
set count=0
if not exist %file% echo cannot find file - %file% & goto :EOF
:: Search for string - and get it's line number
for /F "delims=:" %%a in ('findstr /N /I /C:"%searchString%" "%file%"') do set searchLine=%%a
if not defined searchLine echo cannot find string - %searchString% - in file - %file% & goto :EOF
:: Read file into variables - by line number
for /F "delims=~!" %%b in ('type %file%') do (
set /a count=!count!+1
set line!count!=%%b
)
:: Edit the one line
set line%searchLine%=%repString%
:: Empty file and write new contents
del %file%
for /L %%c in (1,1,!count!) do echo !line%%c!>>%file%
pause
You can change the echo on the last for loop to output to a different file, maybe %file%.new
or something, and then remove the del
command.