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Full Discussion: Performance issue with 'grep' command for huge file size
Operating Systems HP-UX Performance issue with 'grep' command for huge file size Post 302574542 by rwuerth on Thursday 17th of November 2011 12:51:38 PM
Old 11-17-2011
Don't use a loop to get this done, your processing the 2.5GB details.txt file for each name in emp.txt. So if you had 2 names in emp.txt your processing 5GB of detail.txt. 10 names = 25GB. It doesn't scale well that way.

Try this:

Code:
 
grep -F -f emp.txt details.txt

Then you are only processing details.txt once, and of course however big emp.txt is.

Using -F might also save some time. If you don't have the '-F' option look for 'fgrep'.
But being on HP-UX the standard 'grep' should have the -F option available.
Last edited by rwuerth; 11-17-2011 at 01:59 PM.. Reason: I'm scatter brained today. Keep thinking of things to add, after the fact.
These 2 Users Gave Thanks to rwuerth For This Post:
arb_1984 thanhdat
 

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LEARN ABOUT DEBIAN

x2sys_merge

X2SYS_MERGE(1gmt)					       Generic Mapping Tools						 X2SYS_MERGE(1gmt)

NAME

       x2sys_merge - Merge an updated COEs tables

SYNOPSIS

       x2sys_merge -Amain_COElist.d -Mnew_COElist.d

DESCRIPTION

       x2sys_merge  will read two crossovers data base and output the contents of the main one updated with the COEs in the second one. The second
       file should only contain updated COEs relatively to the first one.  That is, it MUST NOT contain any new  two  tracks  intersections  (This
       point  is  NOT checked in the code). This program is useful when, for any good reason like file editing NAV correction or whatever, one had
       to recompute only the COEs between the edited files and the rest of the database.

       -A     Specify the file main_COElist.d with the main crossover error data base.

       -M     Specify the file new_COElist.d with the newly computed crossover error data base.

OPTIONS

       No space between the option flag and the associated arguments.

       EXAMPLES
	      To update the main COE_data.txt with the new COEs estimations saved in the smaller COE_fresh.txt, try

	      x2sys_merge -ACOE_data.txt -MCOE_fresh.txt > COE_updated.txt

SEE ALSO

       x2sys_binlist(1), x2sys_cross(1), x2sys_datalist(1), x2sys_get(1), x2sys_init(1), x2sys_list(1), x2sys_put(1), x2sys_report(1)

GMT 4.5.7							    15 Jul 2011 						 X2SYS_MERGE(1gmt)
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