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Top Forums Shell Programming and Scripting Bash - Inserting non printable character(s) in string variable Post 302962772 by jcdole on Friday 18th of December 2015 07:09:35 AM
Old 12-18-2015
Quote:
Originally Posted by RudiC
Not sure I understand. You want to eliminate non-printable chars from a string?
in pseudo code :
Code:
 MY_VAR=$L_TEMP
while read -N 1 ; do
   A_CHAR="$REPLY"
   if [[ $A_CHAR is not A_PRINTABLE_CHARACTER ]] ; then
    MY_VAR=""
    break
   fi
done <<<"$L_TEMP"

if [[ ! z $MY_VAR ]] ; then
    OK KEEP MY_VAR
else
    CALCULATE ANOTHER MY_VAR
fi

MY_VAR should set to null if it contains one or more not printable character
Somethings like
Code:
grep -E "[all characters are printable]"

my current filter is
Code:
grep -E "[one or more characters are printable]"

---------- Post updated at 13:09 ---------- Previous update was at 12:54 ----------

I have try
Code:
grep -e '[^[:print:]]'

Which seems not working
 

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ppmtopgm(1)						      General Commands Manual						       ppmtopgm(1)

NAME
ppmtopgm - convert a portable pixmap into a portable graymap SYNOPSIS
ppmtopgm [ppmfile] DESCRIPTION
Reads a portable pixmap as input. Produces a portable graymap as output. The output is a "black and white" rendering of the original image, as in a black and white photograph. The quantization formula used is .299 r + .587 g + .114 b. Note that although there is a pgmtoppm program, it is not necessary for simple conversions from pgm to ppm , because any ppm program can read pgm (and pbm ) files automatically. pgmtoppm is for colorizing a pgm file. Also, see ppmtorgb3 for a different way of converting color to gray. And ppmdist generates a grayscale image from a color image, but in a way that makes it easy to differentiate the original colors, not necessarily a way that looks like a black and white photograph. QUOTE
Cold-hearted orb that rules the night Removes the colors from our sight Red is gray, and yellow white But we decide which is right And which is a quantization error. SEE ALSO
pgmtoppm(1),ppmtorgb3(1),rgb3toppm(1),ppmdist(1),ppm(5),pgm(5) AUTHOR
Copyright (C) 1989 by Jef Poskanzer. 10 April 2000 ppmtopgm(1)
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