如何为Bash脚本中yt-dlp的指定输出内容添加着色？

问题背景 #

我有一个Bash脚本用来下载Rumble频道最新2集视频，用yt-dlp的-w参数避免覆盖已存在文件。现在想给输出里的**"Destination"及其文件名**、"has already been downloaded"提示添加着色，方便查看。原脚本如下：

cd /tmp
EPI=$(curl -s https://rumble.com/c/robbraxman | grep  -m 2 "href=/\v"| awk '{print $5}' |awk -F\> '{print $1}')
for i in ${EPI//href=/http://rumble.com}; do
  printf "\e[1;38;5;212m Downloading \e[1;38;5;196m $i\e[m \n"
  yt-dlp -f mp4-480p -w $i
done

yt-dlp的输出示例：

[Rumble] Extracting URL: http://rumble.com/v2820uk-let-me-show-you-brax.me-privacy-focused-app.html
[Rumble] v2820uk-let-me-show-you-brax.me-privacy-focused-app.html: Downloading webpage
[RumbleEmbed] Extracting URL: https://rumble.com/embed/v25g3g0
[RumbleEmbed] v25g3g0: Downloading JSON metadata
[info] v25g3g0: Downloading 1 format(s): mp4-480p
[download] Let Me Show You Brax.Me - Privacy Focused App [v25g3g0].mp4 has already been downloaded
[download] 100% of   20.00MiB

[Rumble] Extracting URL: http://rumble.com/v2820uk-let-me-show-you-brax.me-privacy-focused-app.html
[Rumble] v2820uk-let-me-show-you-brax.me-privacy-focused-app.html: Downloading webpage
[RumbleEmbed] Extracting URL: https://rumble.com/embed/v25g3g0
[RumbleEmbed] v25g3g0: Downloading JSON metadata
[info] v25g3g0: Downloading 1 format(s): mp4-480p
[download] Destination: Let Me Show You Brax.Me - Privacy Focused App [v25g3g0].mp4
[download]   3.8% of  525.67MiB at    5.79MiB/s ETA 01:27^C

解决方案 #

通过管道将yt-dlp的输出传给sed，匹配目标行并添加ANSI颜色代码。修改后的脚本如下：

cd /tmp
EPI=$(curl -s https://rumble.com/c/robbraxman | grep  -m 2 "href=/\v"| awk '{print $5}' |awk -F\> '{print $1}')
for i in ${EPI//href=/http://rumble.com}; do
  printf "\e[1;38;5;212m Downloading \e[1;38;5;196m $i\e[m \n"
  # 处理yt-dlp输出，添加自定义着色
  yt-dlp -f mp4-480p -w "$i" 2>&1 | sed -E '
      # 给Destination行添加亮蓝色
      s/(\[download\] Destination: .*)/\x1b[1;34m\1\x1b[0m/;
      # 给已下载提示行添加亮绿色
      s/(\[download\] .* has already been downloaded)/\x1b[1;32m\1\x1b[0m/
  '
done

关键说明 #

1. 2>&1：将yt-dlp的标准错误输出（大部分状态信息在此）重定向到标准输出，确保所有内容都能被sed处理
2. sed -E：使用扩展正则表达式，简化复杂行的匹配逻辑
3. 颜色代码说明：
   • \x1b[1;34m：亮蓝色，标记目标文件路径
   • \x1b[1;32m：亮绿色，标记已下载完成的提示
   • \x1b[0m：重置颜色，避免后续输出被持续着色
4. $i用双引号包裹：防止URL中包含空格或特殊字符导致命令执行错误

内容的提问来源于stack exchange，提问作者DenisZ