bash 计算终端输出中的行数
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count number of lines in terminal output
提问by roopunk
couldn't find this on SO. I ran the following command in the terminal:
在 SO 上找不到这个。我在终端中运行了以下命令：
>> grep -Rl "curl" ./
and this displays the list of files where the keyword curl occurs. I want to count the number of files. First way I can think of, is to count the number of lines in the output that came in the terminal. How can I do that?
这将显示出现关键字 curl 的文件列表。我想计算文件的数量。我能想到的第一种方法是计算终端中输出的行数。我怎样才能做到这一点？
回答by Jo?o Silva
回答by JelteF
Putting the comment of EaterOfCode here as an answer.
将 EaterOfCode 的评论放在这里作为答案。
grep itself also has the -c flag which just returns the count
grep 本身也有 -c 标志，它只返回计数
So the command and output could look like this.
所以命令和输出可能看起来像这样。
$ grep -Rl "curl" ./ -c
24
EDIT:
编辑：
Although this answer might be shorter and thus might seem better than the accepted answer (that is using wc). I do not agree with this anymore. I feel like remembering that you can count lines by piping to wc -lis much more useful as you can use it with other programs than grepas well.
尽管这个答案可能更短，因此看起来可能比接受的答案（即使用wc）更好。我不再同意这一点。我觉得记住您可以通过管道计算行数wc -l更有用，因为您可以将它与其他程序一起使用grep。
回答by GCS
Piping to 'wc' could be better IF the last line ends with a newline (I know that in this case, it will)
However, if the last line does not end with a newline 'wc -l' gives back a false result.
如果最后一行以换行符结尾，则管道到 'wc' 可能会更好（我知道在这种情况下，它会）
但是，如果最后一行不以换行符结尾，则 'wc -l' 会返回错误结果。
For example:
例如：
$ echo "asd" | wc -l
Will return 1and
将返回1并
$ echo -n "asd" | wc -l
Will return 0
将返回 0
So what I often use is grep <anything> -c
所以我经常使用的是 grep <anything> -c
$ echo "asd" | grep "^.*$" -c
1
$ echo -n "asd" | grep "^.*$" -c
1
This is closer to reality than what wc -lwill return.
这比wc -l将要返回的更接近现实。
