mirror of
https://git.hardenedbsd.org/hardenedbsd/HardenedBSD.git
synced 2024-12-19 06:22:24 +01:00
104 lines
3.2 KiB
Groff
104 lines
3.2 KiB
Groff
.\" Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org>
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code and documentation must retain the above
|
|
.\" copyright notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.Dd June 29, 2023
|
|
.Dt LIBSTDBUF 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm libstdbuf
|
|
.Nd preloaded library to change standard streams initial buffering
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
library is meant to be preloaded with the
|
|
.Ev LD_PRELOAD
|
|
environment variable to as to change the initial buffering
|
|
of standard input, standard output and standard error streams.
|
|
.Pp
|
|
Although you may load and configure this library manually,
|
|
an utility,
|
|
.Xr stdbuf 1 ,
|
|
can be used to run a command with the appropriate environment variables.
|
|
.Sh ENVIRONMENT
|
|
Each stream can be configured independently through the following
|
|
environment variables (values are defined below):
|
|
.Bl -tag -width size -offset indent
|
|
.It Ev _STDBUF_I
|
|
Initial buffering definition for the standard input stream
|
|
.It Ev _STDBUF_O
|
|
Initial buffering definition for the standard output stream
|
|
.It Ev _STDBUF_E
|
|
Initial buffering definition for the standard error stream
|
|
.El
|
|
.Pp
|
|
Each variable may take one of the following values:
|
|
.Bl -tag -width size -offset indent
|
|
.It Qq 0
|
|
unbuffered
|
|
.It Qq L
|
|
line buffered
|
|
.It Qq B
|
|
fully buffered with the default buffer size
|
|
.It Ar size
|
|
fully buffered with a buffer of
|
|
.Ar size
|
|
bytes (suffixes 'k', 'M' and 'G' are accepted)
|
|
.El
|
|
.Sh EXAMPLE
|
|
In the following example, the stdout stream of the
|
|
.Xr awk 1
|
|
command
|
|
will be fully buffered by default because it does not refer
|
|
to a terminal.
|
|
.Nm
|
|
is used to force it to be line-buffered so
|
|
.Xr vmstat 8 Ns 's
|
|
output will not stall until the full buffer fills.
|
|
.Bd -literal -offset indent
|
|
# vmstat 1 | LD_PRELOAD=/usr/lib/libstdbuf.so \\
|
|
STDBUF_1=L awk '$2 > 1 || $3 > 1' | cat -n
|
|
.Ed
|
|
.Pp
|
|
See
|
|
.Xr stdbuf 1
|
|
for a simpler way to do this.
|
|
.Sh SEE ALSO
|
|
.Xr rtld 1 ,
|
|
.Xr stdbuf 1
|
|
.Sh HISTORY
|
|
The
|
|
.Nm
|
|
library first appeared in
|
|
.Fx 8.4 .
|
|
.Sh AUTHORS
|
|
.An -nosplit
|
|
The original idea of the
|
|
.Nm
|
|
command comes from
|
|
.An Padraig Brady
|
|
who implemented it in the GNU coreutils.
|
|
.An Jeremie Le Hen
|
|
implemented it on
|
|
.Fx .
|