【问题】
I have a pattern file and another text file. I want to see what are the patterns in the pattern file which are missing in the text file. The whole lines in the pattern file will do. Any bash/grep/awk solutions?

while read config_opt
do
    if ! grep $config_opt $your_text_file > /dev/null 2>&1; then
        echo -e $config_opt;
     fi
done < $your_pattern_file

【回答】
上面提到的算法是找出“pattern file”和“another text file”的“差集”，用 grep 可以做到，但太慢了。可以试试集算器，不仅可以实现更丰富的算法，性能也会好很多。代码如下：