const charnum=5 '在每行五个字符内
const a="1.txt" '记得保存为\r\n的格式
const c="aaa" '你要查找的字符串
const d="bbb" '你要替换的字符串
set fso=createobject("scripting.filesystemobject")
set re=new regexp
re.pattern="^(.{0,"&charnum-1&"})"&c
re.global=true
re.multiline=true
fso.createtextfile(a,true).write re.replace(fso.opentextfile(a,1).readall,"$1"&d)