/usr/bin/stdbuf

Usage: /usr/bin/stdbuf OPTION... COMMAND
Run COMMAND, with modified buffering operations for its standard streams.

Mandatory arguments to long options are mandatory for short options too.
  -i, --input=MODE   adjust standard input stream buffering
  -o, --output=MODE  adjust standard output stream buffering
  -e, --error=MODE   adjust standard error stream buffering
      --help
         display this help and exit
      --version
         output version information and exit

If MODE is 'L' the corresponding stream will be line buffered.
This option is invalid with standard input.

If MODE is '0' the corresponding stream will be unbuffered.

Otherwise MODE is a number which may be followed by one of the following:
KB 1000, K 1024, MB 1000*1000, M 1024*1024, and so on for G,T,P,E,Z,Y,R,Q.
Binary prefixes can be used, too: KiB=K, MiB=M, and so on.
In this case the corresponding stream will be fully buffered with the buffer
size set to MODE bytes.

NOTE: If COMMAND adjusts the buffering of its standard streams ('tee' does
for example) then that will override corresponding changes by 'stdbuf'.
Also some filters (like 'dd' and 'cat' etc.) don't use streams for I/O,
and are thus unaffected by 'stdbuf' settings.

Exit status:
  125  if the stdbuf command itself fails
  126  if COMMAND is found but cannot be invoked
  127  if COMMAND cannot be found
  -    the exit status of COMMAND otherwise

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/stdbuf>
or available locally via: info '(coreutils) stdbuf invocation'