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.Dd April 28, 2012 .Dt STDBUF 1 .Os .Sh NAME .Nm stdbuf .Nd change standard streams initial buffering .Sh SYNOPSIS .Nm .Op Fl e Ar bufdef .Op Fl i Ar bufdef .Op Fl o Ar bufdef .Op Ar command Op ... .Sh DESCRIPTION .Nm is used to change the initial buffering of standard input, standard output and/or standard error streams for .Ar command . It relies on .Xr libstdbuf 3 which is loaded and configured by .Nm through environment variables.
p The options are as follows: l -tag -width Ds t Fl e Ar bufdef Set initial buffering of the standard error stream for .Ar command as defined by .Ar bufdef
q see Sx BUFFER DEFINITION . t Fl i Ar bufdef Set initial buffering of the standard input stream for .Ar command as defined by .Ar bufdef
q see Sx BUFFER DEFINITION . t Fl o Ar bufdef Set initial buffering of the standard output stream for .Ar command as defined by .Ar bufdef
q see Sx BUFFER DEFINITION . .El .Sh BUFFER DEFINITION Buffer definition is the same as in .Xr libstdbuf 3 : l -tag -width size -offset indent t Qq 0 unbuffered t Qq L line buffered t Qq B fully buffered with the default buffer size t Ar size fully buffered with a buffer of .Ar size bytes (suffixes 'k', 'M' and 'G' are accepted) .El .Sh EXAMPLES 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. d -literal -offset indent # vmstat 1 | stdbuf -o L awk '$2 > 1 || $3 > 1' | cat -n .Ed .Sh SEE ALSO .Xr libstdbuf 3 , .Xr setvbuf 3 .Sh HISTORY The .Nm utility 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 .