Question

I have the following problem using UNIX Commands. I wish to go through a large number of files and convert them using a command that converts them. My idea is to work like this: command *.fileending > *.newfileending

The problem is that I wish to keep the file-names and only replace the file-ending. Thus filename.fileending should become filename.newfileending. How do I achieve this?

Answer 1

Use a for loop:

for file in *.krn; do
  hum2mid "$file" -o "${file%.krn}.mid"
done

In a single line: for file in *.krn; do hum2mid "$file" -o "${file%.krn}.mid"; done

---

To apply the command to files and subdirectories recursively, use the find|xargs pattern:

find -type f -name '*.krn' -print0 \
  | xargs -0 -n1 sh -c 'hum2mid "$1" -o "/destination/dir/$(basename ${1%.krn}.mid)"' -

Note that this will overwrite already converted files, if a file from another directory has the same name.