尘丶

一.

@echo off&setlocal enabledelayedexpansion
for /f "delims=" %%a in (1.txt) do (
    echo;%%a|findstr "^abcd">nul&&(
    echo;%%a
    if not "!num!"=="" echo;!num!
    ) 
    set num=%%a
)
pauseCOPY

二

@echo off&setlocal enabledelayedexpansion
for /f "delims=" %%a in (1.txt) do (
    if !n!==2 echo;%%a&set n=
    echo;%%a|findstr "^abcd">nul&&(
    echo;%%a&set /a n+=2
    if not "!num!"=="" echo;!num!
    ) 
    set num=%%a
)
pauseCOPY

尘丶

二

@echo off&setlocal enabledelayedexpansion
setlocal enabledelayedexpansion
(for /l %%a in (1,1,30) do set/p n%%a=)<1.txt
for /f "delims=" %%a in (1.txt) do (
set num=%%a&set /a n+=1&set /a s=!n!-1&set /a k=!n!+1
if "!num:~,4!"=="abcd" (
    call,echo;上一行:%%n!s!%%
    echo;%%a
    call,echo;下一行:%%n!k!%%
  )
)
pauseCOPY