Pasted

#!/bin/bash
###############################################################################
# This script takes two files as input: file1 (file.txt) which is in form of
# hello here i am [tag]
# hello [tag] world
# File two (tags.txt) which is in form of
# blaa blaa
# blaa blaa1
# And then it produces output, 3rd file (output.txt), with the results like
# hello here i am blaa blaa
# hello here i am blaa blaa1
# hello blaa blaa world
# hello blaa blaa1 world 
###############################################################################
# Hint: Debug lines can be removed
# Hint: run like ./tags-replace.sh file.txt tags.txt output.txt
###############################################################################
# by Security XIII on Dec 16 - 2014
 
while read -r line; do 
# DEBUG # echo "line is: $line"
    for WORD in $line; do
    # DEBUG # echo "word in line is: $WORD"
        if [[ $WORD == "[tag]" ]]; then
            # DEBUG # echo "found tag!"
            while read -r line2; do 
            # DEBUG # echo "adding this to $3: $longrow $line2"
            echo "$longrow $line2" >> $3
            done < "$2"
        else
        # DEBUG # echo "adding this to longrow: $WORD"
        longrow+="$WORD "
        fi
    done
done < "$1"