Sometimes you need a file of some size (possibly for testing purposes). On Linux, you can use dd to create one.
Let's say you want a 23 MB file called test.file. You would then run this:
dd if=/dev/zero of=test.file bs=1048576 count=23
The block size (bs) is set to 1 MB (1024^2 bytes) here, writing 23 such chunks makes the file 23 MB big.\
Adjust to your needs.
This linux command might also come in handy in a Ruby program. It could be used like:
mb = 23
mb_string, _error_str, _status = Open3.capture3('dd if=/dev/zero bs=1048576 count=1')
tempfile = Tempfile.open('some_file.txt') do |file|
mb.times { file.write(mb_string) }
file
end
Fun fact
Using /dev/zero for input writes zeros only, making the output file incredibly well compressible. If you want the opposite, just use /dev/urandom.
Posted by Arne Hartherz to makandra dev (2011-07-18 10:35)