count number of files in a different folder code example

Example 1: How to count number of files in each directory

du -a | cut -d/ -f2 | sort | uniq -c | sort -nr

Example 2: number all files in a folder

a=1
for i in *.jpg; do
  new=$(printf "%04d.jpg" "$a") #04 pad to length of 4
  mv -i -- "$i" "$new"
  let a=a+1
done