wget 訪問一個url默認是把主機的響應內容保存到文件
比如:
$ wget http://www.baidu.com
--2019-08-14 12:49:08-- http://www.baidu.com/
正在解析主機 www.baidu.com (www.baidu.com)... 163.177.151.110, 163.177.151.109
正在連接 www.baidu.com (www.baidu.com)|163.177.151.110|:80... 已連接。
已發出 HTTP 請求，正在等待迴應... 200 OK
長度： 2381 (2.3K) [text/html]
正在保存至: “index.html”
index.html 100% [=========================================================================>] 2.33K --.-KB/s in 0.001s
2019-08-14 12:49:08 (3.62 MB/s) - 已保存 “index.html” [2381/2381])
如何將輸出的內容輸出到stdout呢？這裏就用到了-O選項，下面是從wget使用說明(man wget)中摘抄的關於-O選項的原文描述：
-O file
–output-document=file
The documents will not be written to the appropriate files, but all will be concatenated together and written to file.
If - is used as file, documents will be printed to standard output, disabling link conversion. (Use ./- to print to a file literally named -.)
-O可以指定輸出文件，當-用作輸出文件時，wget將輸出打印到標準輸出(stdout).OK,問題解決，-O配合-q就可以將主機響應發送到標準輸出了：
$ wget -q -O - http://www.baidu.com
<!DOCTYPE html>
<!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=http://s1.bdstatic.com/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn"></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新聞</a> <a href=http://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地圖</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>視頻</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>貼吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登錄</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登錄</a>');</script> <a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多產品</a> </div> </div> </div> <div id=ftCon> <div id=ftConw> <p id=lh> <a href=http://home.baidu.com>關於百度</a> <a href=http://ir.baidu.com>About Baidu</a> </p> <p id=cp>©2017 Baidu <a href=http://www.baidu.com/duty/>使用百度前必讀</a> <a href=http://jianyi.baidu.com/ class=cp-feedback>意見反饋</a> 京ICP證030173號 <img src=//www.baidu.com/img/gs.gif> </p> </div> </div> </div> </body> </html>