bash 脚本中的 printf 命令返回“无效数字”
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/12845997/
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
printf command inside a script returns "invalid number"
提问by Ferdinando Randisi
I can't get printfto print a variable with the %e descriptor in a bash script. It would just say
我无法printf在 bash 脚本中使用 %e 描述符打印变量。它只会说
#!/bin/bash
a=14.9
printf %e 14.9;
I know this is likely a very easy question, but I'm fairly new to bash and always used echo. Plus I couldn't find an answer anywhere.
我知道这可能是一个非常简单的问题，但我对 bash 还很陌生并且总是使用echo. 另外，我在任何地方都找不到答案。
when run i get
跑步时我得到
$ ./test.text
./test.text: line 3: printf: 14.9: invalid number
0,000000
therefore my problem is the locale variable LC_NUMERIC: it is set so that i use commas as decimal separators. Indeed, it is set to an european localization:
因此我的问题是语言环境变量 LC_NUMERIC：它的设置使我使用逗号作为小数点分隔符。事实上，它被设置为欧洲本地化：
$ locale | grep NUM
LC_NUMERIC="it_IT.UTF-8"
I thought I set it to en_US.UTF-8, but evidently I didn't. Now the problem switches to find how to set my locale variable. Simply using
我以为我将它设置为 en_US.UTF-8，但显然我没有。现在问题切换到查找如何设置我的语言环境变量。简单地使用
$ LC_NUMERIC="en_US.UTF-8"
won't work.
不会工作。
采纳答案by Keith Thompson
This:
这个：
LC_NUMERIC="en_US.UTF-8" printf %e 14.9
sets $LC_NUMERIConly for the duration of that one command.
$LC_NUMERIC仅在该命令的持续时间内设置。
This:
这个：
export LC_NUMERIC="en_US.UTF-8"
sets $LC_NUMERIConly for the duration of the current shell process.
设置$LC_NUMERIC仅在当前外壳进程的持续时间。
If you add
如果添加
export LC_NUMERIC="en_US.UTF-8"
to your $HOME/.bashrcor $HOME/.bash_profile, it will set $LC_NUMERICfor all bash shells you launch.
到您的$HOME/.bashrcor $HOME/.bash_profile，它将$LC_NUMERIC为您启动的所有 bash shell设置。
Look for existing code that sets $LC_NUMERICin your .bashrcor other shell startup files.
查找$LC_NUMERIC在您的.bashrc或其他 shell 启动文件中设置的现有代码。
回答by Janito Vaqueiro Ferreira Filho
You could have a locale problem, and it wasn't expecting a period. Try:
您可能遇到了语言环境问题，并且没有预料到一个时期。尝试：
LC_NUMERIC="en_US.UTF-8" printf %e 14.9
回答by pedz
I bumped into this error and found this page. In my case, it was 100% pilot error.
我遇到了这个错误并找到了这个页面。就我而言，这是 100% 的飞行员错误。
month=2
printf "%02d" month
it should be
它应该是
printf "%02d" "${month}"
or more simply
或者更简单
printf "%02d" $month
