Shell Programming and Scripting

while read col1 col2 col3
do
  my set of of instructions
done < input.txt

while read col1 col2 col3
do
echo $col3
if [["$col3"="white"]]; then
        print " matched"
else
        print "not matched"
fi
done < input.txt

while read col1 col2 col3
do
echo $col3
if [ "$col3" = "white" ]; then
        print "white"
elif [ "$col3" = "brown" ]; then
        print "brown"
else
        print "not matched"
fi
done < input.txt

while read col1 col2 col3 rest
   do
   case $col3 in
     (white) printf "%s\n%s\n" "*colors are random: yes" "*colors are light: yes";;
     (brown) printf "%s\n%s\n" "*colors are dark: no" "*colors are random: no:" ;;
     (*)     continue;;
   esac
   done <input.txt >>insert.txt

print "white" >> insert.txt

while ...
do
...
done >> insert.txt