bash 如何同时 grep 多行（来自另一个命令的输出）？
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How do I grep multiple lines (output from another command) at the same time?
提问by peonicles
I have a Linux driver running in the background that is able to return the current system data/stats. I view the data by running a console utility (let's call it dump-data) in a console. Alldata is dumped every time I run dump-data. The output of the utility is like below
我有一个在后台运行的 Linux 驱动程序，它能够返回当前的系统数据/统计信息。我通过在控制台中运行控制台实用程序（我们称之为dump-data）来查看数据。所有的数据转储每次运行时转储数据。该实用程序的输出如下所示
Output:
- A=reading1
- B=reading2
- C=reading3
- D=reading4
- E=reading5
...
- variableX=readingX
...
The list of readings returned by the utility can be really long. Depending on the scenario, certain readings would be useful while everything else would be useless.
该实用程序返回的读数列表可能非常长。根据场景的不同，某些读数会很有用，而其他一切都是无用的。
I need a way to grep only the useful readings whose names might have have nothing in common (via a bash script). I.e. Sometimes I'll need to collect A,D,E; and other times I'll need C,D,E.
我需要一种方法来仅 grep 名称可能没有共同点的有用读数（通过 bash 脚本）。即有时我需要收集 A、D、E；其他时候我需要 C、D、E。
I'm attempting to graph the readings over time to look for trends, so I can't run something like this:
我正在尝试绘制随时间变化的读数以寻找趋势，因此我无法运行这样的操作：
# forgive my pseudocode
Loop
dump-data | grep A
dump-data | grep D
dump-data | grep E
End Loop
to collect A,D,E as that would actually give me readings from 3 separate calls of dump-data as that would not be accurate.
收集 A、D、E，因为这实际上会给我来自 3 个单独的转储数据调用的读数，因为这不准确。
回答by Igor Chubin
If you want to save all result of grep in the same file, you can just join all expressions in one:
如果要将 grep 的所有结果保存在同一个文件中，您可以将所有表达式合并为一个：
grep -E 'expr1|expr2|expr3'
But if you want to have results (for expr1, expr2 and expr3) in separate files, things are getting more interesting.
但是如果你想在单独的文件中得到结果（对于 expr1、expr2 和 expr3），事情就会变得更有趣。
You can do this using tee >(command).
您可以使用tee >(command).
For example, here I process the same pipe with thre different commands:
例如，在这里我使用三个不同的命令处理相同的管道：
$ echo abc | tee >(sed s/a/_a_/ > file1) | tee >(sed s/b/_b_/ > file2) | sed s/c/_c_/ > file3
$ grep "" file[123]
file1:_a_bc
file2:a_b_c
file3:ab_c_
But the command seems to be too complex.
但是命令似乎太复杂了。
I would better save dump-dataresults to a file and then grep it.
我最好将dump-data结果保存到一个文件中，然后 grep 它。
TEMP=$(mktemp /tmp/dump-data-XXXXXXXX)
dump-data > ${TEMP}
grep A ${TEMP}
grep B ${TEMP}
grep C ${TEMP}
回答by scai
You can use dump-data | grep -E "A|D|E". Note the -Eoption of grep. Alternatively you could use egrepwithout the -Eoption.
您可以使用dump-data | grep -E "A|D|E". 注意-Egrep的选项。或者，您可以在egrep没有-E选项的情况下使用。
回答by Vijay
you can simply use:
你可以简单地使用：
dump-data | grep -E 'A|D|E'
