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Full Discussion: Avoiding external utilities
Top Forums Shell Programming and Scripting Avoiding external utilities Post 303010825 by rovf on Monday 8th of January 2018 05:42:18 AM
Old 01-08-2018
Well, first to the usage of fgrep: I don't think you will notice any time different to egrep. The main advantage of fgrep is not speed, but convenience: With fgrep, you don't have to escape characters which have a special meaning inside a regexp.

Also, note that egrep and fgrep are obsolete; the recommended form is
Code:
grep -E

and
Code:
grep -F

. Of course, especially when typing from the command line, fgrep is faster to type than grep -F.

Not to the problem at hand: While I don't see how you can avoid an external utility (unless you write your own shell version of grep, which is possible, but not necessarily faster when it comes to large input), you can - if you are using bash or zsh - at least get rid of the pipe:

Code:
grep -F  'i am on the first line'  <<<$MASSIVETEXT

 

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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)
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