count number of files (based on file extension) in multiple folders

Question

I think it's best described with an example

parent1 (located inside /home/myuser
  - folder1
    - test11.png
    - test11.txt
    - folder11
      - test111.png
    - folder12
      - test121.png
      - test122.png
  - folder2
    - test21.png

if I can my script

get-number-of-files-per-folder "parent" png

the output should be:

folder1: 4
folder2: 1

at the moment, I'm using this command but it seems it counts all the files and not just the file extension I listed.

find /home/myuser/parent -maxdepth 1 -mindepth 1 -type d -exec sh -c 'echo "{} : $(find "{}" -iname "*png" -type f | wc -l)" file\(s\)' \;

How do I know it's wrong? because when I ran this

find /home/myuser/parent -iname '*jpg' -type f | wc -l

it says I have zero JPG files but the script above says I have xx files inside a folder.

Answer 1

Simple shell script approach:

#!/bin/sh

if [ "$#" -ne 2 ]; then
    echo "Usage: $0 directory extension" >&2
    exit 1
fi
cd "$1" || exit 1
for d in *; do
    [ -d "$d" ] || continue
    printf "%s: %i\n" "$d" \
        "$(find "$d" -type f -name "*.$2" -printf '1\n' | wc -l)"
done

… that just uses shell to iterate through all the files/directories in your target directory (well, except for hidden ones starting with .). It ignores non-directories, and for directories prints out the name followed by the file count (obtained by using find and wc). The find … -printf '1\n' is so that find just prints 1 for each file it finds—not printing the file name avoids all issues with, e.g., newlines in file names. And we just need to count the lines, nothing more.

Answer 2

Assuming GNU find, and assuming your filenames don't have embedded newlines:

find /path/to/parent1 -mindepth 2 -type f -iname '*.png' -printf '%P\n' | \
    sed 's#/.*##' | \
    sort | \
    uniq -c

Answer 3

find + awk approach for your current folder structure /home/myuser/parent1/<folder>:

find /home/myuser/parent1 -type f -name "*.png" \
     | awk -F'/' '{ a[$5]++ }END{ for(i in a) print i,a[i] }'

• $5 - points to a folder name at the needed level (adjust this if your folder structure is different; it should be two more than directory depth of the parent. (So for /tmp/parent1 it'd be $4, and for /home/myuser/Documents/parent1 it'd be $6).