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extract a line from a file using the line number

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# 8  
Old 01-22-2009
Head tail combo is best for large volumes
I had two files with 1.28e+06 * 2 bits of info; I wanted to plot every 256 lines for each file. I am using gnuplot.

From my experience the slowest was to use the 'every' command for gnuplot, as it would load the entire file in to memory seemingly for each tiny plot. Using sed to extract a specific line was just as slow; I found this to be because after you have extracted the part you need, the rest of the file is read for good measure.

Using the head, tail combo (which I thought I would like to avoid) is orders of magnitude faster, however, it gets slightly slower (still fastest I have tried) as you progress through the file.
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LEARN ABOUT LINUX

cabextract

CABEXTRACT(1)						      General Commands Manual						     CABEXTRACT(1)

NAME

       cabextract - program to extract files from Microsoft cabinet (.cab) archives

SYNOPSIS

       cabextract [-ddir] [-f] [-Fpattern] [-h] [-l] [-L] [-p] [-q] [-s] [-t] [-v]  cabinet files ...

DESCRIPTION

       cabextract  is  a  program that un-archives files in the Microsoft cabinet file format (.cab) or any binary file which contains an embedded
       cabinet file (frequently found in .exe files).

       cabextract will extract all files from all cabinet files specified on the command line.

       To extract a multi-part cabinet consisting of several files, only the first cabinet file needs to be given as an argument to cabextract	as
       it  will  automatically	look  for the remaining files. To prevent cabextract from extracting cabinet files you did not specify, use the -s
       option.

OPTIONS

       A summary of options is included below.

       -d dir Extracts all files into the directory dir.

       -f     When testing or extracting cabinet files, corrupted MSZIP blocks will be ignored. A warning will be printed  if  a  corrupted  MSZIP
	      block is encountered.

       -F pattern
	      Only  files with names that match the shell pattern pattern shall be listed, tested or extracted. On non-GNU systems, this match may
	      be case-sensitive.

       -h     Prints a page of help and exits.

       -l     Lists the contents of the given cabinet files, rather than extracting them.

       -L     When extracting cabinet files, makes each extracted file's name lowercase.

       -p     Files shall be extracted to standard output.

       -q     When extracting cabinet files, suppresses all messages except errors and warnings.

       -s     When testing, listing or extracting cabinets which span multiple files, only cabinet files given on the command line shall be used.

       -t     Tests the integrity of the cabinet. Files are decompressed, but not written to disk or standard output.  If  the	file  successfully
	      decompresses, the MD5 checksum of the file is printed.

       -v     If given alone on the command line, prints the version of cabextract and exits. Given with a list of cabinet files, it will list the
	      contents of the cabinet files.

AUTHOR

       This manual page was written by Stuart Caie <kyzer@4u.net>, based on the one written by Eric Sharkey <sharkey@debian.org>, for  the  Debian
       GNU/Linux system.

SEE ALSO

       lcab(1)

								 October 30, 2005						     CABEXTRACT(1)