How to create a file with a given size in Linux?

For testing purposes I have to generate a file of a certain size (to test an upload limit).

What is a command to create a file of a certain size on Linux?

Answer

For small files:

dd if=/dev/zero of=upload_test bs=file_size count=1

Where file_size is the size of your test file in bytes.

For big files:

dd if=/dev/zero of=upload_test bs=1M count=size_in_megabytes