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Help capturing and reformatting buffered and unbuffered output

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Old 09-27-2005
Help capturing and reformatting buffered and unbuffered output
Ok, so I have a shell script which runs a specific command, and that command sends it's output to the display. At certain times, the command sends buffered output, and at other times, the command sends unbuffered output in the form of a % progress bar, so if I run the command, the output I receive is similar to this:
$ commandname
Did some internal check...done (this line is buffered)
Did something else...done (this line is buffered)
Performing task: (this line is buffered)
0....10....20....30...etc (this line is unbuffered, and sends output to the display one character at a time)

I would like to somehow capture and reformat both the buffered and unbuffered output so that I can strip out all the command's output, and replace it with my own output. Without getting too specific, what commands can you recommend to do this? What I'd like to to is for each line of buffered output, replace it with different output, or no output at all, and for the unbuffered line, either change the formatting so that when the command sends a period, it prints something else. I realize I can do some pretty detailed stuff with sed, but am honestly not that experienced with it. Can anybody give some suggestions, guidance on how to go about this? To give an example of simple reformatting of the commands output, I could have all buffered output to be sent to /dev/null, and once the unbuffered output starts, send one line stating that all internal tests passed, then start sending the unbuffered output to the display again?

Sorry if this makes no sense, but any help is appreciated.
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LEARN ABOUT HPUX

setvbuf_unlocked

setbuf(3S)																setbuf(3S)

NAME

       setbuf(), setvbuf(), setlinebuf() - assign buffering to a stream file

SYNOPSIS


   Obsolescent Interface
DESCRIPTION

       can  be	used after a stream has been opened but before it is read or written.  It causes the array pointed to by buf to be used instead of
       an automatically allocated buffer.  If buf is the NULL pointer input/output will be completely unbuffered.

       A constant defined in the header file, tells how big an array is needed:

       can be used after a stream has been opened but before it is read or written.  type determines how stream is to be buffered.   Legal  values
       for type (defined in are:

	      causes input/output to be fully buffered.

	      causes output to be line buffered;
			  the buffer will be flushed when a newline is written, the buffer is full, or input is requested.

	      causes input/output to be completely unbuffered.

       When  an  output stream is unbuffered, information is queued for writing on the destination file or terminal as soon as written; when it is
       buffered, many characters are saved up and written as a block.  When the output stream is line-buffered, each line of output is queued  for
       writing on the destination terminal as soon as the line is completed (that is, as soon as a new-line character is written or terminal input
       is requested).  can also be used to explicitly write the buffer.

       If buf is not the NULL pointer, the array it points to is used for buffering instead of an automatically allocated buffer (from size speci-
       fies  the  size of the buffer to be used.  The constant in is suggested as a good buffer size.  If input/output is unbuffered, buf and size
       are ignored.

       By default, output to a terminal is line buffered and all other input/output is fully buffered.

       is used to change stream from block-buffered or unbuffered to line-buffered.  can be used any time the file descriptor is active.

   Obsolescent Interface
       assigns buffering to a stream file.

DIAGNOSTICS

       If an illegal value for type or size is provided, return a non-zero value.  Otherwise, the value returned will be zero.

   Note
       A common source of error is allocating buffer space as an "automatic" variable in a code block, then failing to close  the  stream  in  the
       same block.

       Allocating a buffer of size or bytes does not necessarily imply that all of size or bytes are used for the buffer area.

AUTHOR

       and were developed by HP.

SEE ALSO

       flockfile(3S), fopen(3S), getc(3S), malloc(3C), putc(3S), stdio(3S), thread_safety(5), glossary(9).

STANDARDS CONFORMANCE

																	setbuf(3S)