bash 如何递归地使用 JpegTran（命令行）来优化子目录中的所有文件？
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How to recursivly use JpegTran (command line) to optimise all files in subdirs?
提问by slycat
i have Photos in multiple directories. I want to use jpegtran (command line tool) to recursivly go through each one, optimise it, and save it (overwrite it)
我在多个目录中有照片。我想使用 jpegtran（命令行工具）递归遍历每一个，优化它，并保存（覆盖它）
if they are all in one folder i use this
如果它们都在一个文件夹中，我会使用它
for JPEG in *.jpg ; do jpegtran -optimize $JPEG > $JPEG; done
but i can't get it working recursivly and overwriting the same file (rather than to a new filename)
但我无法让它递归工作并覆盖同一个文件（而不是新文件名）
any tips?
有小费吗？
回答by Bas
find /the/image/path -name "*.jpg" -type f -exec jpegtran -copy none -optimize -outfile {} {} \;
回答by Hai Vu
How about using the findcommand:
如何使用find命令：
find /your/dir -name '*.jpg' -exec echo jpegtran -optimize {} \;
Run the command, if you like the output, remove echoto execute it.
运行命令，如果您喜欢输出，请删除echo以执行它。
回答by Ярослав Рахматуллин
It is usually a whole lot easier to use findin such cases, because what you want to do is acton a few filenames. The findutility will give you those names. Assuming you have GNU (or maybe even BSD) tools, the following example will illustrate this common scenario.
它通常是更容易使用一大堆发现在这种情况下，因为你想做的事是行为上的一些文件名。该发现工具会给你这些名字。假设您拥有 GNU（甚至 BSD）工具，以下示例将说明这种常见情况。
For example:
例如：
$ find ~/images/wallpapers/TEMP/ -type f -iname '*jpg' \
-exec sh -c 'jpegtran -outfile {}.out -optimize {}; mv {}.out {} ' \;
- findlooks for all files ending with jpg in the TEMP folder, recursively.
- For every full file pathfound (denoted by `{}'), findwill run the command given to -exec
- the -exec option cheats and runs several commands instead of one through sh
- find以递归方式查找 TEMP 文件夹中所有以 jpg 结尾的文件。
- 对于找到的每个完整文件路径（用“{}”表示），find将运行给 -exec 的命令
- -exec 选项会欺骗并运行多个命令，而不是通过sh运行一个命令
Notes
笔记
cat file > fileis not allowed because simultaneously reading from, and writing to the same file is not a well defined or even supported operation in bash.
cat file > file不允许，因为同时读取和写入同一个文件在bash 中定义不明确，甚至不受支持。
