Creating file that will not grow beyond a size defined

#dd if=/dev/sda of=./file.txt bs=1M count = 100

(to create a file of 100 MB size)

# mkfs.ext4 -t ext4 file.txt

#mkdir /tmp/file

#sudo mount -t ext4 file.txt /tmp/file

#touch /tmp/file/file1

This will create a file which will not grow beyond 100 MB.

very useful when we are creating log files or file on which we want to set limit.