今天我們來詳細講解下，Linux瀏覽文件的三種命令，它們分別是：cat、less、more！

cat命令: 一次性在終端中顯示文件的所有內容

cat Facebook首席運營官桑德伯格《Lean\ In》.txt

cat命令顯示出多少行呢？

參數：n 由 1 開始對所有輸出的行數進行編號

cat -n Facebook首席運營官桑德伯格《Lean\ In》.txt

cat命令還可以連接多個文本的內容一起輸出

cat -n hello.txt word.txt

less命令: 分頁顯示文件內容

less和cat最大的區別是：less命令會分一頁一頁地顯示文件內容，cat會一次性全部顯示

less Facebook首席運營官桑德伯格《Lean\ In》.txt

這時我們會看到 less命令不會一次性讀取 ‘Facebook首席運營官桑德伯格《Lean\ In》.txt’ 文本里的全部內容，而是會分頁讀取，每一頁讀取內容的多少是由你的終端大小來決定的

less命令瀏覽文件的快捷鍵：

注意：這里快捷鍵的字母都是區分大小寫的

less命令瀏覽文件高級快捷鍵的使用

“=”鍵：顯示當前頁面的內容是文件中第幾行到第幾行，按Enter鍵撤銷

Facebook首席運營官桑德伯格《Lean\ In》.txt lines 5-10/287 byte 4308/171635 3% (press RETURN)

下面我們就對這段描述信息座椅詳細的解釋：

Facebook首席運營官桑德伯格《Lean\ In》.txt: 表示當前正在讀取文件的名稱

lines 5-10/287： 表示這個文本總共有287行，當前正在讀取的是5-10行

byte 4308/171635: 表示文本總共有171635個字符，當前讀取了4308個字符

%3： 表示當前讀取的內容占了文本內容總共的 %3

h鍵：進入快捷鍵的幫助文檔，按q鍵退出

/(斜杠)：進入搜索模式

如：搜索關鍵字 more

要想在搜索中跳轉到下一個符合的內容，可以按n鍵，按N鍵可以跳到上一個符合的內容

more命令

more命令和less命令相似，但沒有less命令強大

如：more命令不能往后翻頁，只能一路往前翻頁

這是因為more命令是在less命令之前出現的

注：這是Facebook首席運營官桑德伯格《Lean In》的部分篇章，大家可以用這部分篇章來對cat、less命令做一次動手實操的練習，這樣可以幫助大家更好的理解less命令的強大之處

I GOT PREGNANT with my first child in the summer of 2004. At the time, I was running the online sales and operations groups at Google. I had joined the company three and a half years earlier when it was an obscure start-up with a few hundred employees in a run-down office building. By my first trimester, Google had grown into a company of thousands and moved into a multibuilding campus.

My pregnancy was not easy. The typical morning sickness that often accompanies the first trimester affected me every day for nine long months. I gained almost seventy pounds, and my feet swelled two entire shoe sizes, turning into odd-shaped lumps I could see only when they were propped up on a coffee table. A particularly sensitive Google engineer announced that “Project Whale” was named after me.

One day, after a rough morning spent staring at the bottom of the toilet, I had to rush to make an important client meeting. Google was growing so quickly that parking was an ongoing problem, and the only spot I could find was quite far away. I sprinted across the parking lot, which in reality meant lumbering a bit more quickly than my absurdly slow pregnancy crawl. This only made my nausea worse, and I arrived at the meeting praying that a sales pitch was the only thing that would come out of my mouth. That night, I recounted these troubles to my husband, Dave. He pointed out that Yahoo, where he worked at the time, had designated parking for expectant mothers at the front of each building.

The next day, I marched in—or more like waddled in—to see Google founders Larry Page and Sergey Brin in their office, which was really just a large room with toys and gadgets strewn all over the floor. I found Sergey in a yoga position in the corner and announced that we needed pregnancy parking, preferably sooner rather than later. He looked up at me and agreed immediately, noting that he had never thought about it before.

To this day, I’m embarrassed that I didn’t realize that pregnant women needed reserved parking until I experienced my own aching feet. As one of Google’s most senior women, didn’t I have a special responsibility to think of this? But like Sergey, it had never occurred to me. The other pregnant women must have suffered in silence, not wanting to ask for special treatment. Or maybe they lacked the confidence or seniority to demand that the problem be fixed. Having one pregnant woman at the top—even one who looked like a whale—made the difference.