How to count the total number of files in all sub-directories?

Question

l have a directory called /data/ which contains two sub-directories: /data/train/ and /data/test/. train and test each contain 101 sub-directories (101 directories in train and 101 in test).

These directories contain jpeg images. I want to loop through all the directories to:

1. Count the total number of images
2. Count the number of images contained in each directory

Answer 1

Read man find, and do something like

find /data/train /data/test -type f -print | wc -l

for dirname in $(find /data/train /data/test -type d -print) ; do
    /bin/echo -e -n "$dirname\t"
    find $dirname -type f -print | wc -l
done

Answer 2

Python has appropriate utilities for such job built in already. As one-liner this would be done as so:

$ python -u -c 'from os import walk,path; print "\n".join([str(len(f)) +" "+r for r,d,f in walk(".")])'

Or as script as so:

#!/usr/bin/env python
import os
import sys
for root,dirs,files in os.walk(sys.argv[1]):
    print(root,len(files))

Notice that in script version you're meant to call script with directory as positional parameter:

$ ./count_files.py my_dir/

Answer 3

In pure bash:

for dir in /data/*/; do
    files=( "$dir"/*/* )
    printf "%s\t%s\n" "$dir:" "${#files[@]}"
done

The output would be something like:

/data/test:     5432
/data/train:    1234