Limitations of tac/cat? Post: 302459459

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Top Forums Shell Programming and Scripting Limitations of tac/cat? Post 302459459 by durden_tyler on Monday 4th of October 2010 05:27:54 PM

10-04-2010

Registered User

Quote:

Originally Posted by 127.0.0.1

...I was also told such a command wouldn't work with a "one million" line text file.... is this true?, ...

It's easy to check that that's not true.

Code:

$
$ # create a million-line file
$ perl -le 'for (1..1_000_000){print "this is line $_"}' >file_1mil.txt
$
$ wc file_1mil.txt
 1000000  4000000 20888896 file_1mil.txt
$
$
$ time tac file_1mil.txt
this is line 1000000
this is line 999999
this is line 999998
this is line 999997
this is line 999996
this is line 999995
this is line 999994
this is line 999993
this is line 999992
this is line 999991
this is line 999990
...
...
...
this is line 10
this is line 9
this is line 8
this is line 7
this is line 6
this is line 5
this is line 4
this is line 3
this is line 2
this is line 1
 
real    4m9.095s
user    0m7.186s
sys     0m21.328s
$
$

It does work with a million lines and I think, is pretty fast.

tyler_durden

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LEARN ABOUT DEBIAN

blockdiag

BLOCKDIAG(1)						      General Commands Manual						      BLOCKDIAG(1)

NAME

       blockdiag - generate block-diagram image file from spec-text file.

SYNOPSIS

       blockdiag [options] file

DESCRIPTION

       This manual page documents briefly the blockdiag commands.

       blockdiag is a program that generate block-diagram image file from spec-text file.

OPTIONS

       These  programs	follow	the  usual  GNU  command  line	syntax, with long options starting with two dashes (`-').  A summary of options is
       included below.	For a complete description, see the SEE ALSO.

       --version
	      show program's version number and exit

       -h, --help
	      Show summary of options

       -a, --antialias
	      Pass diagram image to anti-alias filter

       -c FILE, --config=FILE
	      read configurations from FILE

       -o FILE
	      write diagram to FILE

       -f FONT, --font=FONT
	      use FONT to draw diagram

       --fontmap=FONT
	      use FONTMAP file to draw diagram

       -s, --separate
	      Separate diagram images for each group

       -T TYPE
	      Output diagram as TYPE format

       --nodoctype
	      Do not output doctype definition tags (SVG only)

       --no-transparency
	      do not make transparent background of diagram (PNG only)

SEE ALSO

       The programs are documented fully by
       http://tk0miya.bitbucket.org/blockdiag/build/html/index.html

AUTHOR

       blockdiag was written by Takeshi Komiya <i.tkomiya@gmail.com>

       This manual page was written by Kouhei Maeda <mkouhei@palmtb.net>, for the Debian project (and may be used by others).

								   May	9, 2011 						      BLOCKDIAG(1)

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