bash for loop中没有扩展名的文件名 [英] File name without extension in bash for loop

问题描述

在这样的for循环中:

In a for loop like this one:

for f in `ls *.avi`; do echo $f; ffmpeg -i $f $f.mp3; done

$ f将是完整的文件名，包括扩展名.例如，对于song1.avi，命令的输出将是song1.avi.mp3.有没有办法只获取song1，而没有for循环中的.avi?

$f will be the complete filename, including the extension. For example, for song1.avi the output of the command will be song1.avi.mp3. Is there a way to get only song1, without the .avi from the for loop?

我想有很多方法可以使用awk或其他类似的工具来做到这一点，但我希望还有一些更简单的方法.

I imagine there are ways to do that using awk or other such tools, but I'm hoping there's something more straight forward.

谢谢

推荐答案

使用bash参数扩展

${f%%.*}

请注意，您需要贪婪的版本，因为文件名中包含多个点.

Note that you need the greedy version because there are multiple dots in the file name.

来自bash手册:

$ {parameter％word}

$ {parameter %% word}

该单词被扩展以产生一个模式，就像文件名扩展一样.如果该模式与参数的扩展值的结尾部分匹配，则扩展的结果是具有最短匹配模式(％"情况)或最长匹配模式("%%"情况)的参数值已删除.如果参数是"@"或""，则模式去除操作将依次应用于每个位置参数，并且扩展名是结果列表.如果parameter是下标为'@'或''的数组变量，则将模式删除操作依次应用于数组的每个成员，并且扩展为结果列表.

The word is expanded to produce a pattern just as in filename expansion. If the pattern matches a trailing portion of the expanded value of parameter, then the result of the expansion is the value of parameter with the shortest matching pattern (the ‘%’ case) or the longest matching pattern (the ‘%%’ case) deleted. If parameter is ‘@’ or ‘’, the pattern removal operation is applied to each positional parameter in turn, and the expansion is the resultant list. If parameter is an array variable subscripted with ‘@’ or ‘’, the pattern removal operation is applied to each member of the array in turn, and the expansion is the resultant list.

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