Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: In memory grep of a large file.
Top Forums Shell Programming and Scripting In memory grep of a large file. Post 302960513 by shoaibjameel123 on Monday 16th of November 2015 12:31:17 PM
Old 11-16-2015
Thanks, drl. I can see some improvement using your command as I can see that all words in "obama|primaries|water" are searched at the same time. This can surely help reduce the amount of iterations needed.

I can also improve upon your script a little bit by doing this:
Code:
LC_ALL=C grep -owP "(\w+\s){0,2}(obama|primaries|water)(\s\w+){0,2}" big_file.txt

I also found another way using GNU parallel. I have tried several variations, but the variation which I am interested in is this (given here GNU Parallel):

Code:
parallel --pipepart --block 100M -a big_file.txt --fifo cat words_file.txt | parallel --pipe -L1000 --round-robin grep -f - {}

But the above code does not do what I really want, so I tried modifying to this:
Code:
parallel --pipepart --block 100M -a big_file.txt --fifo cat  words_file.txt | parallel --pipe -L1000 --round-robin grep -fowP "(?:\w+\s){0,2}$name(?:\s\w+){0,2}" -  {}

There is still some issues about how to include those word patterns from words_file.txt into this command.
 

10 More Discussions You Might Find Interesting

1. Linux

shmat() Failure While Using a Large Amount of Shared Memory

Hi, I'm developing a data processing pipeline with multiple stages, with data being moved between the stages using shared memory segments. The size of the data is typically of the order of hundreds of megabytes, and there are typically a few tens of main shared memory segments each of size... (2 Replies)
Discussion started by: theicarusagenda
2 Replies

2. HP-UX

How can I get memory usage or anything that show memory used from sar file?

Refer from title: How can i get memory used or anything that can show memory from sar file example on solaris:- we can use sar with option to show memory used at time that sar crontab run. on HP-UX, it not has option to see memory used. But i think it may be have some parameter or some... (1 Reply)
Discussion started by: panithat
1 Replies

3. UNIX for Dummies Questions & Answers

Grep alternative to handle large numbers of files

I am looking for a file with 'MCR0000000716214' in it. I tried the following command: grep MCR0000000716214 * The problem is that the folder I am searching in has over 87000 files and I am getting the following: bash: /bin/grep: Arg list too long Is there any command I can use that can... (6 Replies)
Discussion started by: runnerpaul
6 Replies

4. AIX

amount of memory allocated to large page

We just set up a system to use large pages. I want to know if there is a command to see how much of the memory is being used for large pages. For example if we have a system with 8GB of RAm assigned and it has been set to use 4GB for large pages is there a command to show that 4GB of the *GB is... (1 Reply)
Discussion started by: daveisme
1 Replies

5. Shell Programming and Scripting

grep error: range endpoint too large

Hi, my problem: gzgrep "^.\{376\}8301685001120" filename /dev/null ###ERROR ### grep: RE error 11: Range endpoint too large. Whats my mistake? Is the position 376 to large for grep??? Thanks. (2 Replies)
Discussion started by: Timmää
2 Replies

6. Shell Programming and Scripting

grep/fgrep/egrep for a very large matrix

All, I have a problem with grep/fgrep/egrep. Basically I am building a 200 times 200 correlation matrix. The entries of this matrix need to be retrieved from another very large matrix (~100G). I tried to use the grep/fgrep/egrep to locate each entry and put them into one file. It looks very... (1 Reply)
Discussion started by: realwindfly
1 Replies

7. UNIX for Advanced & Expert Users

Out of Memory error when free memory size is large

I was running a program and it stopped and showed "Out of Memory!". at that time, the RAM used by this process is around 4G and the free memory size of the machine is around 30G. Does anybody know what maybe the reason? this program is written with Perl. the OS of the machine is Solaris U8. And I... (1 Reply)
Discussion started by: lilili07
1 Replies

8. Shell Programming and Scripting

Severe performance issue while 'grep'ing on large volume of data

Background ------------- The Unix flavor can be any amongst Solaris, AIX, HP-UX and Linux. I have below 2 flat files. File-1 ------ Contains 50,000 rows with 2 fields in each row, separated by pipe. Row structure is like Object_Id|Object_Name, as following: 111|XXX 222|YYY 333|ZZZ ... (6 Replies)
Discussion started by: Souvik
6 Replies

9. UNIX for Dummies Questions & Answers

virtual memory and diff'ing very large files

(0 Replies)
Discussion started by: uiop44
0 Replies

10. Shell Programming and Scripting

Large search replace using sed results in memory problem.

I have one big file of size 9GB (big_file.txt). This big file has sentences and paragraphs like any usual English document. I have another file consisting of replacement strings for sed to use. The file name is replace.sed and each entry in one line looks like this: s/\<shout\>/shout/g s/\<b is... (2 Replies)
Discussion started by: shoaibjameel123
2 Replies

LEARN ABOUT DEBIAN

parallel-slurp

PARALLEL-SLURP(1)														 PARALLEL-SLURP(1)

NAME

       parallel-slurp - copy files from listed hosts

SYNOPSIS

       parallel-slurp [OPTIONS] -h hosts.txt -L destdir remote local

DESCRIPTION

       pssh provides a number of commands for executing against a group of computers, using SSH. It's most useful for operating on clusters of
       homogenously-configured hosts.

       parallel-slurp gathers specified files from hosts you listed.

OPTIONS

       -r --recursive
	   recusively copy directories (OPTIONAL)

       -L --localdir
	   output directory for remote file copies

       -h --hosts
	   hosts file (each line "host[:port] [user]")

       -l --user
	   username (OPTIONAL)

       -p --par
	   max number of parallel threads (OPTIONAL)

       -o --outdir
	   output directory for stdout files (OPTIONAL)

       -e --errdir
	   output directory for stderr files (OPTIONAL)

       -t --timeout
	   timeout (secs) (-1 = no timeout) per host (OPTIONAL)

       -O --options
	   SSH options (OPTIONAL)

       -v --verbose
	   turn on warning and diagnostic messages (OPTIONAL)

EXAMPLE

       An example to copy /home/irb2/foo.txt from each host. Files gathered will be stored in /tmp/outdir/hostname/foo.txt.

	   # prallel-slurp -h hosts.txt -L /tmp/outdir -l irb2 
		    /home/irb2/foo.txt foo.txt

ENVIRONMENT

       All four programs take similar sets of options. All of these options can be set using the following environment variables:

       o   PSSH_HOSTS
       o   PSSH_USER
       o   PSSH_PAR
       o   PSSH_OUTDIR
       o   PSSH_VERBOSE
       o   PSSH_OPTIONS

SEE ALSO

       parallel-ssh(1), parallel-scp(1), parallel-nuke(1), parallel-rsync(1), ssh(1)

AUTHOR

       Brent N. Chun <bnc@theether.org>

COPYING

       Copyright: 2003, 2004, 2005, 2006, 2007 Brent N. Chun

NOTES

	1. bnc@theether.org
	   mailto:bnc@theether.org

								    03/30/2009							 PARALLEL-SLURP(1)
All times are GMT -4. The time now is 11:24 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy