Linux man pages

Section (1) stdbuf

Linux manual pages	Section 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 _zsingle_quotesz_L_zsingle_quotesz_ the corresponding stream will be line buffered. This option is invalid with standard input.

If MODE is _zsingle_quotesz_0_zsingle_quotesz_ 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. 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 (_zsingle_quotesz_tee_zsingle_quotesz_ does for example) then that will override corresponding changes by _zsingle_quotesz_stdbuf_zsingle_quotesz_. Also some filters (like _zsingle_quotesz_dd_zsingle_quotesz_ and _zsingle_quotesz_cat_zsingle_quotesz_ etc.) don_zsingle_quotesz_t use streams for I/O, and are thus unaffected by _zsingle_quotesz_stdbuf_zsingle_quotesz_ settings.

Note

If COMMAND adjusts the buffering of its standard streams (_zsingle_quotesz_tee_zsingle_quotesz_ does for example) then that will override corresponding changes by _zsingle_quotesz_stdbuf_zsingle_quotesz_. Also some filters (like _zsingle_quotesz_dd_zsingle_quotesz_ and _zsingle_quotesz_cat_zsingle_quotesz_ etc.) don_zsingle_quotesz_t use streams for I/O, and are thus unaffected by _zsingle_quotesz_stdbuf_zsingle_quotesz_ settings.

EXAMPLES

tail -f access.log | stdbuf -oL cut -d _zsingle_quotesz_ _zsingle_quotesz_ -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/>