stdbuf(1) — Linux manual page


STDBUF(1)                     User Commands                    STDBUF(1)

NAME         top

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

SYNOPSIS         top

       stdbuf OPTION... COMMAND

DESCRIPTION         top

       Run COMMAND, with modified buffering operations for its standard

       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

              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

EXAMPLES         top

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

BUGS         top

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

AUTHOR         top

       Written by Padraig Brady.

REPORTING BUGS         top

       GNU coreutils online help:
       Report any translation bugs to

COPYRIGHT         top

       Copyright © 2023 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.

SEE ALSO         top

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

COLOPHON         top

       This page is part of the coreutils (basic file, shell and text
       manipulation utilities) project.  Information about the project
       can be found at ⟨⟩.  If you
       have a bug report for this manual page, see
       ⟨⟩.  This page was obtained
       from the tarball coreutils-9.4.tar.xz fetched from
       ⟨⟩ on 2023-12-22.  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to

GNU coreutils 9.4              August 2023                     STDBUF(1)

Pages that refer to this page: setbuf(3)