Something

filelength=wc -l array.txtfor ((i=1;i<=filelength;i+=1)) do         if [ sed -n '$i/<key>.*<\/key>/p' array.txt ]                for ((j=i;j<=filelength;j+=1)); do                        if [ sed -n '$i /<string>.*<\/string>/p' array.txt ] then                                # insert code that will take key and string and insert them into an array                        fi                done        fidone