This causes cp to detect and omit large blocks of nulls. Sparse files are useful for implying a lot of disk space without actually having to write it all out.
http://en.wikipedia.org/wiki/Sparse_file
You can use it in a pipe too:
dd if=/dev/zero bs=1M count=5 |cp --sparse=always /dev/stdin SPARSE_FILE
Show Sample Output
Prints the path/filename and sparseness of any sparse files (files that use less actual space than their total size because the filesystem treats large blocks of 00 bytes efficiently).
Prints the path/filename and sparseness of any sparse files (files that use less actual space than their total size because the filesystem treats large blocks of 00 bytes efficiently). Uses a Tasker-esque field separator of more than one character to ensure uniqueness. Show Sample Output
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