Bash grep 命令以开头或结尾
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Bash grep command starts with or ends with
提问by Daniel Del Core
I'm after a command that will return results based on a pattern match that starts with or ends with a the given pattern.
我正在执行一个命令，该命令将根据以给定模式开头或结尾的模式匹配返回结果。
This is what i have so far.
这是我到目前为止。
"cat input.txt | grep "^in|in$"
My main problem is that i cant get the (or) to work but i can get them to work individually.
我的主要问题是我无法让（或）工作，但我可以让他们单独工作。
Thanks for your help in advance.
提前感谢您的帮助。
回答by Kent
try this:
尝试这个：
grep "^in\|in$" input.txt
by default, grep use BRE, you have to escape the |. Or use grep's -E or -P, in order to avoid escaping those char with special meaning.
默认情况下，grep 使用BRE，您必须转义|. 或者使用 grep's -E or -P，以避免转义那些具有特殊含义的字符。
P.S, the catis no necessary.
PS，cat没必要。
回答by Jotne
This awkshould work:
这awk应该有效：
awk '/^start|end$/' file
It will print all lines starting with startor ending with end
它将打印以开头start或结尾的所有行end
cat file
nothing
start with this
or it does have an end
or the end is near
awk '/^start|end$/' file
start with this
or it does have an end
回答by Galzzly
Have you thought of using egrep rather than grep? Using the following should work for what you're after:
你有没有想过使用 egrep 而不是 grep ？使用以下内容应该适用于您所追求的内容：
egrep "^in|in$" input.txt
There's no need to have the cat at the start, the above will work fine.
不需要一开始就养猫，上面的就可以了。
