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Top Forums UNIX for Advanced & Expert Users Help optimizing sort of large files Post 302926737 by DGPickett on Wednesday 26th of November 2014 01:53:38 PM
Old 11-26-2014
Well, you are approaching the ideal, that the first pass create N files with one sorted string on each, and the next pass is the final merge. If you fall short, then there needs to be at least one intermediate pass to merge to fewer strings per file. Each pass has to take the io time to copy the entire file, so less passes is better.

Head moition is an old phobia, perhaps persisting because you can still hear the seeks on some drives. Ofthe the average seek is less than the average latency. Modern drives cache everything once they arrive on cylinder, so some latency may be paid back in fast access to the cached, later sectors. Large AU and smart buffering in HW and software helps ensure more data for each possible seek. If the disk is not defragged, and especially if it has a low AU, you may have a lot of seeks in a sequential read or write.
 

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WRAP-AND-SORT(1)					      General Commands Manual						  WRAP-AND-SORT(1)

NAME
wrap-and-sort - wrap long lines and sort items in Debian packaging files SYNOPSIS
wrap-and-sort [options] DESCRIPTION
wrap-and-sort wraps the package lists in Debian control files. By default the lists will only split into multiple lines if the entries are longer than 80 characters. wrap-and-sort sorts the package lists in Debian control files and all .install files. Beside that wrap-and-sort removes trailing spaces in these files. This script should be run in the root of a Debian package tree. It searches for control, control.in, copyright, copyright.in, install, and *.install in the debian directory. OPTIONS
-h, --help Show this help message and exit. -a, --wrap-always Wrap all package lists in the Debian control file even if the entries are shorter than 80 characters and could fit in one line line. -s, --short-indent Only indent wrapped lines by one space (default is in-line with the field name). -b, --sort-binary-packages Sort binary package paragraphs by name. -k, --keep-first When sorting binary package paragraphs, leave the first one at the top. Unqualified debhelper(7) configuration files are applied to the first package. -n, --no-cleanup Do not remove trailing whitespaces. -d path, --debian-directory=path Location of the debian directory (default: ./debian). -f file, --file=file Wrap and sort only the specified file. You can specify this parameter multiple times. All supported files will be processed if no files are specified. -v, --verbose Print all files that are touched. AUTHORS
wrap-and-sort and this manpage have been written by Benjamin Drung <bdrung@debian.org>. Both are released under the ISC license. DEBIAN
Debian Utilities WRAP-AND-SORT(1)
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