changing col(1) command stdout as fully buffered?


 
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Old 06-09-2006
changing col(1) command stdout as fully buffered?

Hi All,

I am talking about unix col(1) command used for some reverse line filtering etc.
And I notice that the stdout of this command is line buffered i.e. the stdout will flush the data in its buffer line by line. So the number of writes performed by stdout are more.

So now if I make stdout as fully buffered it will reduce the write hits. Smilie

But if I do these changes I think there will some problems
-> when slow terminals use col(1) as command , then the turn around time will get reduce for it self.
eg: cat file | col -b | lp
Here lp will receive data in terms of buffer size but before it was receving in terms of each lines.

So can I change change col(1) command's stdout to fully buffered?

So do any of you know some more problems related with this change , and can I see some link about col(1) command design stating that it should be either line buffered or fully buffered etc.


Waiting for positive replay,
Sunil kumar.
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STDBUF(1)						    BSD General Commands Manual 						 STDBUF(1)

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: -e bufdef Set initial buffering of the standard error stream for command as defined by bufdef (see BUFFER DEFINITION). -i bufdef Set initial buffering of the standard input stream for command as defined by bufdef (see BUFFER DEFINITION). -o bufdef 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
libstdbuf(3), setvbuf(3) 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. BSD
April 28, 2012 BSD