block2plain.sh

#!/bin/bash
# Convers a stream of blocks of text into lines. Each line has the whole text of the block.
# For example, for this block
#    begin
#    some text tha an script put in block
#    when we want it in a single line
#    because if hard to work with.
#    end
#    begin
#    other interesting text in block
#    that should be a line.
#    end
# It will be converted into
#    begin some text tha an script put in block when we want it in a single line because if hard to work with. end
#    begin other interesting text in block that should be a line. end
if [ -z "$1" ] || [ -z "$2" ]; then
   echo "It's need a regexp that identifies the first line of the block and the last line of it."
   exit 1
fi

BEGIN="$1"
END="$2"
shift 2

sed -n -e "/${BEGIN}/,/${END}/{:x;/${END}/!N;/${END}/b e;b x;:e;s/\n/ /g}" "$@"