/usr/bin/truncate

Usage: /usr/bin/truncate OPTION... FILE...
Shrink or extend the size of each FILE to the specified size

A FILE argument that does not exist is created.

If a FILE is larger than the specified size, the extra data is lost.
If a FILE is shorter, it is extended and the sparse extended part (hole)
reads as zero bytes.

Mandatory arguments to long options are mandatory for short options too.
  -c, --no-create        do not create any files
  -o, --io-blocks        treat SIZE as number of IO blocks instead of bytes
  -r, --reference=RFILE  base size on RFILE
  -s, --size=SIZE        set or adjust the file size by SIZE bytes
      --help
         display this help and exit
      --version
         output version information and exit

The SIZE argument is an integer and optional unit (example: 10K is 10*1024).
Units are K,M,G,T,P,E,Z,Y,R,Q (powers of 1024) or KB,MB,... (powers of 1000).
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.

SIZE may also be prefixed by one of the following modifying characters:
'+' extend by, '-' reduce by, '<' at most, '>' at least,
'/' round down to multiple of, '%' round up to multiple of.

Report bugs to: <bug-coreutils@gnu.org>.
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
Full documentation <https://www.gnu.org/software/coreutils/truncate>
or available locally via: info '(coreutils) truncate invocation'