Top Forums Shell Programming and Scripting Get 20% of lines in File randomly Post 302707167 by chercheur857 on Friday 28th of September 2012 05:55:55 AM
Get 20% of lines in File randomly


This is my code:
nb_lignes=`wc -l $1 | cut -d " " -f1`
for i in $(seq $nb_lignes)
m=`head $1 -n $i | tail -1`

Please how can i change it to get Get 20% of lines in File randomly to apply "command" on each line ? 20% or 40% or 60 % (it's a parameter)

Thank you.

Last edited by Franklin52; 09-28-2012 at 09:07 AM.. Reason: Please use code tags for data and code samples
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ppmtosixel(1)						      General Commands Manual						     ppmtosixel(1)

ppmtosixel - convert a portable pixmap into DEC sixel format SYNOPSIS
ppmtosixel [-raw] [-margin] [ppmfile] DESCRIPTION
Reads a portable pixmap as input. Produces sixel commands (SIX) as output. The output is formatted for color printing, e.g. for a DEC LJ250 color inkjet printer. If RGB values from the PPM file do not have maxval=100, the RGB values are rescaled. A printer control header and a color assignment table begin the SIX file. Image data is written in a compressed format by default. A printer control footer ends the image file. OPTIONS
-raw If specified, each pixel will be explicitly described in the image file. If -raw is not specified, output will default to com- pressed format in which identical adjacent pixels are replaced by "repeat pixel" commands. A raw file is often an order of magni- tude larger than a compressed file and prints much slower. -margin If -margin is not specified, the image will be start at the left margin (of the window, paper, or whatever). If -margin is speci- fied, a 1.5 inch left margin will offset the image. PRINTING
Generally, sixel files must reach the printer unfiltered. Use the lpr -x option or cat filename > /dev/tty0?. BUGS
Upon rescaling, truncation of the least significant bits of RGB values may result in poor color conversion. If the original PPM maxval was greater than 100, rescaling also reduces the image depth. While the actual RGB values from the ppm file are more or less retained, the color palette of the LJ250 may not match the colors on your screen. This seems to be a printer limitation. SEE ALSO
ppm(5) AUTHOR
Copyright (C) 1991 by Rick Vinci. 26 April 1991 ppmtosixel(1)
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