Dividing folder contents into subfolders

Recently, I came across a problem of dividing a folder with N number of files into sub-folders with almost equal number of files each. While with small number of file you may do it easily, when things come to Big Data, its always wiser to run a script.

The requirement can be of two types:

1. Divide N number of files into sub-folders with X number of files each. Number of sub-folders doesn’t matter.
   

   cd /path/to/folder/with/files
   export num_file=1000  #Assuming 1000 files into each sub-folder
   i=0;
   for file_name in *;
   do

   dir_name=dir_$(printf %03d $((i/$num_file)));
   #Direcotry names would be dir_000 … dir_999 and so on.
   mkdir -p $dir_name;
   mv “$file_name” $dir_name;
   let i++;

   done

2. Divide N number of files into X number of sub folders with almost equal number of files. Number of files in each folder doesn’t matter.
   

   cd /path/to/folder/with/files
   export tot_file=$(ls | wc -l)
   echo $tot_file
   export num_folder=24 #Assumming 24 sub-folders, each for an hour.
   export num_file=($(($tot_file/$num_folder)) + 1)
   i=0;
   for file_name in *;
   do

   dir_name=hr_$(printf %02d $((i/$num_file)));
   #Directory names would be hr_00, hr_01 … hr_23
   mkdir -p $dir_name;
   mv “$file_name” $dir_name;
   let i++;

   done