从coursera网站自动下载网课视频2（Linux中bash操作）

上一篇文章（从coursera网站自动下载网课视频（Linux中bash操作））介绍了如何从coursera下载视频，并自动添加中英文字幕。
但是最近下载的时候发现网站有些变化，主要是字幕文件格式调整为vtt了，因此脚本也需要适当变化以下。但是主要操作流程不变。
（1）新建urllist文本文件（不含后缀名，如果需要修改请同时修改bash文件中对应名称），复制网址到urllist文件中，比如某节课中需要下载以下视频。

https://www.coursera.org/learn/market-research/lecture/Gie1W/the-importance-of-marketing-research-its-role-in-marketing-management
https://www.coursera.org/learn/market-research/lecture/CGsWX/the-steps-to-conducting-marketing-research
https://www.coursera.org/learn/market-research/lecture/YjZPs/types-of-market-research
https://www.coursera.org/learn/market-research/lecture/tQYAA/exploratory-descriptive-and-causal-research-part-i
https://www.coursera.org/learn/market-research/lecture/9FE2q/exploratory-descriptive-and-causal-research-part-ii
https://www.coursera.org/learn/market-research/lecture/wgKOP/types-of-experimentation
https://www.coursera.org/learn/market-research/lecture/gf5Uq/validity-reliability
https://www.coursera.org/learn/market-research/lecture/hrIUy/types-of-experimental-designs
https://www.coursera.org/learn/market-research/lecture/eeN0d/primary-data-in-market-research
https://www.coursera.org/learn/market-research/lecture/7DgQD/secondary-data-scales-of-measurement
https://www.coursera.org/learn/market-research/lecture/HiZnM/how-to-design-a-questionnaire
https://www.coursera.org/learn/market-research/lecture/G7uND/how-to-measure-and-scale-our-consumers-attitudes
https://www.coursera.org/learn/market-research/lecture/XsUCr/target-population-and-sampling
https://www.coursera.org/learn/market-research/lecture/IaaQU/categorical-data-metric-data-hypothesis-testing

（2）新建getcoursera2021.sh 文件，复制下面的脚本文件。保存，修改属性，添加执行权限。

#!/bin/bash
##########该工具仅限学习交流使用，不可用于其他目的，一切后果自负##########
######################by Nautilus，20210318######################
###################在coursera.org网自动下载所需视频#################

#####urllist 文件需配置地址
#url="https://www.coursera.org/lecture/intro-international-marketing/introduction-to-specialization-RmskU"

function getVideo(){
     
#建立临时文件夹
randompath=$(date +%s%N)$RANDOM
mkdir "./.${randompath}"
cd "./.${randompath}"

##获取文件url
wget -O htmltmp $1

#文件名
#title=`grep -oP "videoName\".*?.h1" htmltmp`
#title=${title%\<*}
#title=${title#*\>}
#title=${title//" "/"_"}

title=`grep -oP "VideoObject\",\"name\":\".*?.\",\"url\"" htmltmp`
title=${
     title#*"VideoObject\",\"name\":\""}
title=${
     title%"\",\"url\""*}

#视频地址
videourl=`grep -oP "mp4VideoUrl.*?.720p.*?.mp4.*?.\"" htmltmp`
videourl=${
     videourl#*mp4VideoUrl\":\"}
videourl=${
     videourl%\"*}
videourl=${videourl//"\\u002F"/"/"}

#字幕地址
suburl1=`grep -oP "zhCn\":\".*?.vtt\"" htmltmp`
suburl1=${suburl1#*zhCn\":\"}
suburl1=${suburl1%\"*}
suburl1=${suburl1//"\\u002F"/"/"}

suburl2=`grep -oP "\"en\":\".*?.vtt\"" htmltmp`
suburl2=${suburl2#*\"en\":\"}
suburl2=${suburl2%\"*}
suburl2=${suburl2//"\\u002F"/"/"}

##下载文件
wget -O "${title}tmp.mp4" $videourl
wget -O zhcn.vtt "https://www.coursera.org${suburl1}"
wget -O eng.vtt "https://www.coursera.org${suburl2}"

#合并处理
ffmpeg -i "${title}tmp.mp4" -i zhcn.vtt -i eng.vtt -map 0:v -map 0:a -map 1 -map 2  -c:v copy -c:a copy -c:s mov_text -metadata:s:s:0 language=chn -metadata:s:s:1 language=eng "../${title}.mp4"


#扫尾处理
cd "../"
rm -r "./.${randompath}"
}

###
FILENAME="urllist"
for   i  in  `cat $FILENAME` 
do 
getVideo $i
done

（3）执行bash，自动获取所有视频。