今天仔細研究了grep,
例如:文件bookword中
there is a book
there is a book.
there is a book'
there is a book)
there is a 'book
there is a 'book.
there is a (book.
there are some books.
there are some 'books.
there is a handbook.
book
books
handbook
如果只想匹配 book. ,
$ grep -n "[ ]book[.]" bookword
如果想匹配所有的book,
$ grep -n "/<book/>" bookword
這裏有幾個知識點
1. 精確匹配 /< 和 /> 可以去掉如"handbook" 或者"books"這樣的單詞
2. [“[{(]可以用在單詞前,用於匹配符號+單詞這樣的組合, 如: grep "[(]book" bookword
there is a (book.
3. []})"?!.,;:'s], 可以用於單詞後,用於匹配符號+單詞,單詞複數 如 grep "book[.]" bookword
there is a book.
there is a 'book.
there is a (book.
there is a handbook.
4. (^|空格) 可以匹配單詞在行的開始或者一個空格.
5. (空格|$) 可以匹配單詞在行的結尾或者一個空格.