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Top Forums UNIX for Advanced & Expert Users Which cut command is more efficient? Post 302508316 by methyl on Sunday 27th of March 2011 09:00:38 PM
Old 03-27-2011
Quote:
In my early shell-scripting days I wrote scripts that I'm sure would need your 36 processors to function with any efficiency Having CPU power to waste hardly makes it a good idea to do so.
My stats do not show waste of CPU power. They show a CPU power saving by using "cat" because "cut" is less efficient at reading files. However in a single stream environment loading multiple processes in a long pipeline would have been a performance disaster.

In my early days or unix I have dealt with system crashes caused by for example: too many concurrent processes; too many forks; disc buffer overload; mysterious kernel crash etc. . It's hard to even generate these situations on modern systems after an initial large-scale kernel build.


There is a very good O'Reilly book "System Performance Tuning" but do bear in mind that it does not cover very large unix systems adequately.
 

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CUT(1)									FSF								    CUT(1)

NAME
cut - remove sections from each line of files SYNOPSIS
cut [OPTION]... [FILE]... DESCRIPTION
Print selected parts of lines from each FILE to standard output. Mandatory arguments to long options are mandatory for short options too. -b, --bytes=LIST output only these bytes -c, --characters=LIST output only these characters -d, --delimiter=DELIM use DELIM instead of TAB for field delimiter -f, --fields=LIST output only these fields; also print any line that contains no delimiter character, unless the -s option is specified -n with -b: don't split multibyte characters -s, --only-delimited do not print lines not containing delimiters --output-delimiter=STRING use STRING as the output delimiter the default is to use the input delimiter --help display this help and exit --version output version information and exit Use one, and only one of -b, -c or -f. Each LIST is made up of one range, or many ranges separated by commas. Each range is one of: N N'th byte, character or field, counted from 1 N- from N'th byte, character or field, to end of line N-M from N'th to M'th (included) byte, character or field -M from first to M'th (included) byte, character or field With no FILE, or when FILE is -, read standard input. AUTHOR
Written by David Ihnat, David MacKenzie, and Jim Meyering. REPORTING BUGS
Report bugs to <bug-coreutils@gnu.org>. COPYRIGHT
Copyright (C) 2002 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU- LAR PURPOSE. SEE ALSO
The full documentation for cut is maintained as a Texinfo manual. If the info and cut programs are properly installed at your site, the command info cut should give you access to the complete manual. cut (coreutils) 4.5.3 February 2003 CUT(1)
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