bash - bash, treat piped commands as one to capture output

Question

Say I have a set of piped commands in bash:

mysqldump mydatabase  |   head -1100   | tail -n 100

What is the correct / best way to treat that as one command, so I can capture the output.

I tried enclosing the commands in backticks (which as I understand opens a new shell, which seems unnecessary), but got an error.

`mysqldump mydatabase  |   head -1100   | tail -n 100 ` > output.txt  


error mysqldump: Got errno 32 on write

Not sure if the error is related to the bash commands or the mysql (it worked before I added the backticks).

Anyway, I am more interested in how I can treat the piped commands as one / group them for capturing.

score 2 · Accepted Answer

左手命令的标准输出充当右手命令的标准输入，所以mysqldump mydatabase | head -1100 | tail -n 100 > output.txt应该可以工作。

如果你真的要“说清楚”，这应该可行。 ( mysqldump mydatabase | head -1100 | tail -n 100 ) > output.txt

score 2 · Accepted Answer

行中的每个命令都接受一些输入并返回一个输出，因此您可以将其视为传递数据的链。

如果您希望结果显示在控制台中，您只需编写

mysqldump mydatabase | head -1100 | tail -n 100

否则要将其保存在文件中，您将输出重定向到文件，就像这样

mysqldump mydatabase | head -1100 | tail -n 100 > output.txt

score 1 · Accepted Answer

Instead of creating two pipes you can use sed to find sections of line numbers

    mysqldump mydatabase | sed -n '1000,1100p' > output.txt

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