echo 变量后立即带有字母

Question

p=$( power )
echo "Power now: ${p}W"

印刷

Wower now: 357

这毫无意义。这肯定是一个错误吗？

Answer 1

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Wower now: 357\n

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啊，是的，这实际上是以下序列，一个字节接一个字节

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P (0x50)\no (0x6f)\nw (0x77)\ne (0x65)\nr (0x72)\n  (0x20)\nn (0x6e)\no (0x6f)\nw (0x77)\n: (0x3a)\n  (0x20)\n3 (0x33)\n5 (0x35)\n7 (0x37)\njump-back-to-beginning-of-line (0x0d) ## called "carriage return", if you know typewriters\xe2\x80\xa6\nW (0x57)\n

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因此，您的power命令出于人类未知的原因输出357\\r（回车）。

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解决方案：只打印来自 的实际数字power，例如：

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Wower now: 357\n

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或更紧凑：

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P (0x50)\no (0x6f)\nw (0x77)\ne (0x65)\nr (0x72)\n  (0x20)\nn (0x6e)\no (0x6f)\nw (0x77)\n: (0x3a)\n  (0x20)\n3 (0x33)\n5 (0x35)\n7 (0x37)\njump-back-to-beginning-of-line (0x0d) ## called "carriage return", if you know typewriters\xe2\x80\xa6\nW (0x57)\n

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