bash 如何将多个命令的输出重定向到一个文件
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/20355264/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
how to redirect output of multiple commands to one file
提问by user2864207
i have a bash script, that has the following two commands:
我有一个 bash 脚本，它有以下两个命令：
ssh host tail -f /some/file | awk ..... > /some/file &
ssh host tail -f /some/file | grep .... > /some/file &
How can i make the output of both commands be directed into the same file.
如何将两个命令的输出定向到同一个文件中。
采纳答案by glenn Hymanman
Note you can reduce the number of ssh calls:
请注意，您可以减少 ssh 调用的次数：
{ ssh host tail -f /some/file |
tee >(awk ...) >(grep ...) >/dev/null
} > /some/file &
example:
例子：
{ echo foobar | tee >(sed 's/foo/FOO/') >(sed 's/bar/BAR/') > /dev/null; } > outputfile
cat outputfile
fooBAR
FOObar
回答by Jonathan Leffler
Either use 'append' with >>or use braces to encompass the I/O redirections, or (occasionally) use exec:
使用带有>>或使用大括号的“附加”来包含 I/O 重定向，或者（偶尔）使用exec：
ssh host tail -f /some/file | awk ..... > /some/file &
ssh host tail -f /some/file | grep .... >> /some/file &
or:
或者：
{
ssh host tail -f /some/file | awk ..... &
ssh host tail -f /some/file | grep .... &
} > /some/file
or:
或者：
exec > /some/file
ssh host tail -f /some/file | awk ..... &
ssh host tail -f /some/file | grep .... &
After the exec, the standard output of the script as a whole goes to /some/file. I seldom use this technique; I usually use the { ...; }technique instead.
之后exec，整个脚本的标准输出转到/some/file. 我很少使用这种技术；我通常使用这种{ ...; }技术。
Note: You do have to be careful with the braces notation. What I showed will work. Trying to flatten it onto one line requires you to treat the {as if it were a command (followed by a space, for example) and also to treat the }as if it were a command. You must have a command terminator before the }— I used a newline, but an &for background or ;would work too.
注意：您必须小心大括号表示法。我展示的东西会起作用。试图将其展平到一行需要您将 the{视为命令（例如，后跟一个空格）并将 the}视为命令。您必须在}- 我使用换行符之前有一个命令终止符，但&用于背景或;也可以使用。
Thus:
因此：
{ command1; command2; } >/some/file
{ command1 & command2 & } >/some/file
I also have not addressed the issue of why you have two separate tail -foperations running on a single remote file and why you are not using awkpower as a super-grepto handle it all in one — I've only addressed the surface question of how to redirect the I/O of the two commands to one file.
我也没有解决为什么tail -f在一个远程文件上运行两个单独的操作以及为什么不使用awkpower 作为一个超级grep来处理这一切的问题——我只解决了如何重定向的表面问题两个命令对一个文件的 I/O。
回答by twalberg
The best answer to this is to probably get rid of the ssh .... | grep ...line, and modify the awkscript in the other command to add the functionality you were getting from the grepcommand...
对此的最佳答案是可能摆脱该ssh .... | grep ...行，并修改awk另一个命令中的脚本以添加您从grep命令中获得的功能...
That will get rid of any interleaving issues as a bonus side-effect.
这将消除任何交错问题作为额外的副作用。
