fallocate

Reserve or deallocate disk space to files. The utility allocates space without zeroing. More information: https://manned.org/fallocate.

• Reserve a file taking up 700 MiB of disk space:
  fallocate --length {{700M}} {{path/to/file}}
• Shrink an already allocated file by 200 MiB:
  fallocate --collapse-range --length {{200M}} {{path/to/file}}
• Shrink 20 MB of space after 100 MiB in a file:
  fallocate --collapse-range --offset {{100M}} --length {{20M}} {{path/to/file}}