batch script to print previous and next lines of search string in a text file

Question

I have a batch script which will print the entire line of search string into a text file.

for %%i in (log.txt) do (
FINDSTR /G:pattern.txt %%i >> outpu         


        

Answer 1

@echo off
setlocal EnableDelayedExpansion
rem Assemble the list of line numbers
set numbers=
for /F "delims=:" %%a in ('findstr /I /N /C:"error occurred" log.txt') do (
   set /A before=%%a-1, after=%%a+1
   set "numbers=!numbers!!before!: !after!: "
)
rem Search for the lines
(for /F "tokens=1* delims=:" %%a in ('findstr /N "^" log.txt ^| findstr /B "%numbers%"') do echo %%b) > output.txt