You can think of tr as a (very) simplified variant of sed: it will replace one character with another or remove some characters altogether.

您可以将tr看作为sed的(极其)简化的变体：它可以用一个字符来替换另一个字符，或者可以完全除去一些字符。

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Null string variant cannot be converted to a character.

不能将空字符串变量转换为字符。

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A kind of program variant method of Chinese characters based on origin character is put forward by analyzing the original strokes and font feature of Chinese characters.

文章通过讨论汉字的基本笔画及字体特征提出了一种基于原体的汉字程序变体方法。

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