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Top Forums Shell Programming and Scripting Quick way to select many records from a large file Post 302942338 by sea on Monday 27th of April 2015 07:22:23 PM
Old 04-27-2015
Hello and welcome to the forum.

Please use code tags for code block examples, as required by the forum rules.

Not sure on the script, as i dont know csh or ksh.
In bash i'd do:
Code:
while read line;do
   awk -v key="$line" {/^key/} {print $0} records.txt
done<key.txt

Then execute it:
Code:
$SHELL pick_records.s > output.txt

Note that i find "pick_" quite irritating, since you dont pick (as in: select a single entry) anything of something, but run through everything (every line) found.

Half a million (or just 200'000) lines/entries do need their time to be done.
You could figure out a difference by adding time in front of executing the script.
Code:
time $SHELL pick-records.sh

Hope this helps (hth)
 

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RAKE(1) 						 Ruby Programmers Reference Guide						   RAKE(1)

NAME
rake -- Ruby Make SYNOPSIS
rake [--f Rakefile] [--version] [-CGNPgnqstv] [-D [PATTERN]] [-E CODE] [-I LIBDIR] [-R RAKELIBDIR] [-T [PATTERN]] [-e CODE] [-p CODE] [-r MODULE] [--rules] [variable=value] target ... DESCRIPTION
Rake is a simple ruby(1) build program with capabilities similar to the regular make(1) command. Rake has the following features: o Rakefiles (Rake's version of Makefiles) are completely defined in standard Ruby syntax. No XML files to edit. No quirky Makefile syntax to worry about (is that a tab or a space?). o Users can specify tasks with prerequisites. o Rake supports rule patterns to synthesize implicit tasks. o Flexible FileLists that act like arrays but know about manipulating file names and paths. o A library of prepackaged tasks to make building rakefiles easier. OPTIONS
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