NAME
stdbuf —
change standard streams initial
buffering
SYNOPSIS
stdbuf |
[-e bufdef]
[-i bufdef]
[-o bufdef]
[command [...]] |
DESCRIPTION
stdbuf is used to change the initial buffering of
standard input, standard output and/or standard error streams for
command. It relies on
libstdbuf(3) which is loaded and configured by
stdbuf through environment variables.
The options are as follows:
-ebufdef- Set initial buffering of the standard error stream for command as defined by bufdef (see BUFFER DEFINITION).
-ibufdef- Set initial buffering of the standard input stream for command as defined by bufdef (see BUFFER DEFINITION).
-obufdef- Set initial buffering of the standard output stream for command as defined by bufdef (see BUFFER DEFINITION).
BUFFER DEFINITION
Buffer definition is the same as in libstdbuf(3):
- "0"
- unbuffered
- "L"
- line buffered
- "B"
- fully buffered with the default buffer size
- size
- fully buffered with a buffer of size bytes (suffixes 'k', 'M' and 'G' are accepted)
EXAMPLES
In the following example, the stdout stream of the
awk(1) command will be fully buffered by default because it does not
refer to a terminal. stdbuf is used to force it to
be line-buffered so
vmstat(8)'s output will not stall until the full buffer fills.
# vmstat 1 | stdbuf -o L awk '$2 > 1 || $3 > 1' | cat -n
SEE ALSO
HISTORY
The stdbuf utility first appeared in
FreeBSD 8.4.
AUTHORS
The original idea of the stdbuf command
comes from Padraig Brady who implemented it in the
GNU coreutils. Jeremie Le Hen implemented it on
FreeBSD.