Selected Ways to Convert Tabs to Spaces from
#'d items below from:  http://mlawire.blogspot.com/2009/07/convert-tabs-to-spaces.html
    Posted 26th July 2009 by mla for use on Unix/Linux/OSX - found June 2016
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NOTE:  the tab is represented by "\t"  (to replace tab use #6b below)
       changing tabs to 4 spaces in vi, edit/create:  .exrc
                                         set tabstop=4 shiftwidth=4 expandtab
                                         syntax off
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#1 expand/unexpand utilities:   expand < input.txt > output.txt
#2 Sed:                         sed 's/\t/ /g' < input.txt > output.txt
#3 Awk:                         awk '{ gsub(/\t/, "  "); print }' < input.txt > output.txt
#4 Perl                         perl -pe 's/\t/  /g' < input.txt > output.txt
#6a Vim editor:                 :set expandtab   ;     :%retab!  
#6b Vim editor:                 :%s/\t/  /g
#8 cut:                         cut -f1- --output-delimiter='  ' < input.txt > output.txt
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