if [ "${LINE:0:5}" = "data7" ]

Type: SystemDeclarationData;7    
1BN22IN prisoner



U0010000003

prisoner VIII SP

















1
1
25
-1
0
0
0
0
0
Type: SupplyLoad;4
0
0
end;

end;

Type: SystemDeclarationData;7
1BN22IN prisoner CLASS V SP





U0010000004

prisoner CLASS V SP

















1
1
26
-1
0
0
0
0
0
Type: SupplyLoad;4
0
0
end;

end;

Type: SystemDeclarationData;7    
100000056



U0010000003

prisoner VIII SP

















1
1
25
-1
0
0
0
0
0
Type: SupplyLoad;4
0
0
end;

end;

Type: SystemDeclarationData;7
20000056





U0010000004

prisoner CLASS V SP

















1
1
26
-1
0
0
0
0
0
Type: SupplyLoad;4
0
0
end;

end;

#!/bin/bash
changefile="test_csv.csv"         #this is the file the new string is pulled from
Input="test.fplan"    #this is the file that needs changed
I=1

while read LINE
do    #~ find the string that starts with data7
    if [[ "${LINE}" =~ "SystemDeclarationData" ]]
    then
        read LINE    #~ if the string on the next line has the word prisoner then replace it with the string in line 1.
        if [[ "${LINE}" =~ "JDLM" ]]
        then
            head -n$I "$changefile" | tail -n1
            (( I ++ ))    #~ the next instance of the pattern would be replaced by the string in line 2 and so on.
        else echo "$LINE"
        fi
    else echo "$LINE"
    fi
done < "$Input" > /home/bj/Desktop/test_complete