Why the code in a for loop is executed only in the first directory in a bash shell?

Question

Under a directory called a there are many subfolders where I want to do something. The same for all. I do the following but it applies only to the first subdirectory:

for i in "a/*"
    do
            #echo $i
            cd $i
            mkdir test
            mv *_no test
            touch aaa
            cd ..
    done

The above code I want to be executed in every directory under a.

Answer 1

When using globs, you should remove the quotes. If not, the globs is not expanded.

So :

for i in a/*

Answer 2

The first cd chdirs into the first directory (two levels of subdirs). And after that you can't cd into the second because you've only gone back one level so you're not back where you started from. But even then, you're looping over one single value: "a/*".

Since you've put quotes around that, it is not getting expanded.

However you've forgotten to put quotes around $i, so it does get expanded at that point as arguments to cd.

There are a lot of other problems with your code.

Some suggestions of improvements:

for i in a/*/; do
  (
    cd -- "$i" &&
      mkdir -p test || exit
    mv -- *_no test
    touch aaa
  )
done

Answer 3

Quoting $i inside the loop doesn't do anything since a/*/ is already expanded into words. For example if a/*/ expands to a/My Documents/, in the first loop $i = a/My and second loop $i = Documents/ Try

find . -maxdepth 1 -type d | while read i; do
  (
    cd -- "$i" &&
      mkdir -p test || exit
    mv -- *_no test
    touch aaa
  )
done