Manual: gnustdbuf

STDBUF(1)						User Commands						   STDBUF(1)

NAME
       stdbuf - Run COMMAND, with modified buffering operations for its standard streams.

SYNOPSIS
       stdbuf OPTION... COMMAND

DESCRIPTION
       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 corre‐
       sponding 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	cor‐
       responding 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

EXAMPLES
       tail -f access.log | stdbuf -oL cut -d ' ' -f1 | uniq
       This will immediately display unique entries from access.log

BUGS
       On GLIBC platforms, specifying a buffer size, i.e., using fully buffered mode will result in undefined operation.

AUTHOR
       Written by Padraig Brady.

REPORTING BUGS
       GNU coreutils online help: 
       Report any translation bugs to 

SEE ALSO
       Full documentation 
       or available locally via: info '(coreutils) stdbuf invocation'

       Packaged by Ubuntu (9.7-3ubuntu2)
       Copyright © 2025 Free Software Foundation, Inc.
       License GPLv3+: GNU GPL version 3 or later .
       This is free software: you are free to change and redistribute it.
       There is NO WARRANTY, to the extent permitted by law.

GNU coreutils 9.7					January 2026						   STDBUF(1)