Bash – How to list hidden directories, then directories, then hidden files and finally files with ls

Spaces in a file/directory name are fine as long as those names are properly quoted:

find . -maxdepth 1 -name "*.doc" | while IFS= read -r f; do 
    mkdir -- "${f%.doc}"; 
done

For the stated question you can use find:

find . -mindepth 1 ! -type l

will list all files and directories in the current directory or any subdirectories that are not symlinks.

mindepth 1 is just to skip the . current-directory entry. The meat of it is the combination of -type l, which means "is a symbolic link", and !, which means negate the following test. In combination they match every file that is not a symlink. This lists all files and directories recursively, but no symlinks.

If you just want regular files (and not directories):

find . -type f

To include only the direct children of this directory, and not all others recursively:

find . -mindepth 1 -maxdepth 1

You can combine those (and other) tests together to get the list of files you want.

To execute a particular grep on every file matching the tests you're using, use -exec:

find . -type f -exec grep -H 'some pattern' '{}' +

The '{}' will be replaced with the files. The + is necessary to tell find your command is done. The option -H forces grep to display a file name even if it happens to run with a single matching file.