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Shell Programming and Scripting
Need Quick help on Understanding sed Regex
Post 302926437 by junior-helper on Monday 24th of November 2014 12:33:44 PM
11-24-2014
I interpret the sed command as follows:
---------- Post updated at 07:33 PM ---------- Previous update was at 07:32 PM ----------
Oh, too late, again
- If the line is a blank line, it will substitute any number of spaces and tabs with a single space
- If the line contains some text, it will substitute any number of trailing spaces and tabs with a single space
---------- Post updated at 07:33 PM ---------- Previous update was at 07:32 PM ----------
Oh, too late, again
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LEARN ABOUT OPENSOLARIS
ppmtosixel
ppmtosixel(1) General Commands Manual ppmtosixel(1) NAME
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)