For testing shell tips (linux and cygwin) it is often handy to

  • work a test directory
  • make some (tons of!) files

Ok, I suppose you can create directories (mkdir dirname). Now, you can use touch to create (empty) files:

touch a b c d

will create files a, b, c and d.

To create 200 file starting their names with file_, followed with a number and ending with .img, do

mkdir source
cd source
for ((num=0;num<200;num+=1)); do touch file_${num}.img ; done

Now you can tests the shell tips (example).