前提・実現したいこと
macOSでbashでの正規表現の学習をしています。
grepで$記号を用いた行末指定をしようとしたのですが検索パターンが認識されません。

発生している問題
指定したzen.txtファイルにはidea.という文字列が含まれている行があるにも関わらず$を加えると認識されません。

name-no-MacBook-Pro:Desktop name$ grep idea.$ zen.txt
name-no-MacBook-Pro:Desktop name$

該当のソースコード
macOS bash

name-no-MacBook-Pro:~ name$ export GREP_OPTIONS='--color=always'
name-no-MacBook-Pro:~ name$ cd Desktop
name-no-MacBook-Pro:Desktop name$ grep idea.$ zen.txt
name-no-MacBook-Pro:Desktop name$

試したこと

name-no-MacBook-Pro:Desktop name$ grep idea. zen.txt
If the implementation is hard to explain, it's a bad idea.\
If the implementation is easy to explain, it may be a good idea.\
Namespaces are one honking great idea -- let's do more of those!}

補足情報（FW/ツールのバージョンなど）
ターミナル　バージョン2.9.5(421.2)

name-no-MacBook-Pro:Desktop name$ cat zen.txt
{\rtf1\ansi\ansicpg932\cocoartf1671\cocoasubrtf600
{\fonttbl\f0\fnil\fcharset0 Menlo-Regular;}
{\colortbl;\red255\green255\blue255;\red0\green0\blue0;}
{\*\expandedcolortbl;;\csgray\c0;}
\paperw11900\paperh16840\margl1440\margr1440\vieww10800\viewh8400\viewkind0
\pard\tx560\tx1120\tx1680\tx2240\tx2800\tx3360\tx3920\tx4480\tx5040\tx5600\tx6160\tx6720\pardirnatural\partightenfactor0

\f0\fs22 \cf2 \CocoaLigature0 The Zen of Python, by Tim Peters\
\
Beautiful is better than ugly.\
Explicit is better than implicit.\
Simple is better than complex.\
Complex is better than complicated.\
Flat is better than nested.\
Sparse is better than dense.\
Readability counts.\
Special cases aren't special enough to break the rules.\
Although practicality beats purity.\
Errors should never pass silently.\
Unless explicitly silenced.\
In the face of ambiguity, refuse the temptation to guess.\
There should be one-- and preferably only one --obvious way to do it.\
Although that way may not be obvious at first unless you're Dutch.\
Now is better than never.\
Although never is often better than *right* now.\
If the implementation is hard to explain, it's a bad idea.\
If the implementation is easy to explain, it may be a good idea.\
Namespaces are one honking great idea -- let's do more of those!\
}