reading-a-file-backwards.rex

Pipelines v2.1

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 1
 2 /* The following pipeline illustrates the most efficient way to select records that you know
 3 lie toward the end of a large input file. By reading the file in reverse record order; the
 4 target records can be located without unnecessarily traversing a significant portion of
 5 the file.
 6
 7 This approach may be of particular use when extracting data from large 'log-type' files. */
 8
 9 Address Rxpipe
 10
 11 'pipe < rev &installdrive:\&installpath\examples\input\nyse.txt',
 12 '| inside zone(w2) /134700/ /134200/', /* Select the block of records. */
 13 '| buffer rev', /* Reverse the records. */
 14 '| cons' /* Display the records on the console. */
 15
 16 Say 'Hit Enter to close..'
 17 Parse Pull
 18
 19 Exit 0
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