| -i--input | adjust standard input stream buffering |
| -o--output | adjust standard output stream buffering |
| -e--error | adjust standard error stream buffering |
| --help | display this help and exit |
| --version | output version information and exit |
| 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 |
NAME
stdbuf - Run COMMAND, with modified buffering operations for its standard streams.
SYNOPSIS
stdbufOPTION... 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 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
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: <https://www.gnu.org/software/coreutils/> Report any translation bugs to <https://translationproject.org/team/>
SEE ALSO
Full documentation <https://www.gnu.org/software/coreutils/stdbuf> or available locally via: info '(coreutils) stdbuf invocation'
Packaged by Debian (9.7-3) Copyright © 2025 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.