4 ms·

Also fallocate (Linux only though).

• natmaka 4y ago
  dd can do it on an existing file or stream, transforming sequences of 0 it contains into "holes".
  • inopinatus 4y ago
    caveat operator: to ensure the conv=sparse operand achieves the desired outcome, be sure to use an output blocksize equal to st_blksize of the output filesystem.
    • jhugo 4y ago
      or just use `cp --sparse=always` if it's from one file to another
      • inopinatus 4y ago
        That is not so portable, so I recommend sticking with dd.
        • jhugo 4y ago
          Yup, `dd` helps in a lot of situations when you need portability, not just this one. Commands like `cp --sparse=always` aren't worth such a blanket disrecommendation though; if you are working directly at a console as opposed to scripting you typically don't need portability.
          • inopinatus 4y ago
            Again, most of the consoles I work at don’t use GNU coretools.
            • jhugo 4y ago
              Then you obviously can't use this, but many people reading my suggestion can.