为 for 循环提供的文件名列表实际上包含 find .我认为您要执行的操作是提供 find 的 output ，搜索当前目录中或该目录下的所有PNG图片.

The list of filenames you are giving to the for loop literally contains find. I think what you meant to do is give the output of find, searching for all PNG images in or under the current directory, which is

for f in $(find . -iname '*.png'); do convert "$f" "$f".pdf; done

这将不能很好地处理空格.更好的解决方案是只在 find 本身内部运行转换，

This will not handle spaces well. A better solution is to just run the conversion from within find itself,

find "$PWD" -iname '*.png' -execdir convert '{}' '{}'.pdf \;

尽管请注意，最后将使用以 .png.pdf

Although note that you will wind up with filenames ending with .png.pdf