随笔：linux正则表达式ERE模式中的管道符号“|”（代表or）

$ echo "I ate an apple. " | gawk '/apple|banana/{print $0}'
输出：
I ate an apple.

$ echo "I ate a banana. " | gawk '/apple|banana/{print $0}'
输出：
I ate a banana.

$ echo "I ate a peach. " | gawk '/apple|banana/{print $0}'
输出：

(未匹配，无输出)