stdbuf - Run COMMAND, with modified buffering operations for its standard streams.
stdbuf OPTION... COMMAND
Run COMMAND, with modified buffering operations for its standard streams.
Mandatory arguments to long options are mandatory for short options too.
If MODE is L the corresponding stream will be line buffered. This option is invalid with standard input.
-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 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. 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 e.g.) then that will override corresponding settings changed by stdbuf. Also some filters (like dd and cat etc.) dont use streams for I/O, and are thus unaffected by stdbuf settings.
tail -f access.log | stdbuf -oL cut -d -f1 | uniq
This will immedidately display unique entries from access.log
On GLIBC platforms, specifying a buffer size, i.e. using fully buffered mode will result in undefined operation.
Written by Padraig Brady.
Report stdbuf bugs to email@example.com
GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
General help using GNU software: <http://www.gnu.org/gethelp/>
Report stdbuf translation bugs to <http://translationproject.org/team/>
Copyright © 2011 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://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.
The full documentation for stdbuf is maintained as a Texinfo manual. If the info and stdbuf programs are properly installed at your site, the command
should give you access to the complete manual.
info coreutils stdbuf invocation
|GNU coreutils 8.12.197-032bb||STDBUF (1)||September 2011|