Need for the same set of commands for Insert as well as Append

[Marco van Beek]

Hi All,

I think there is a need for the same sort of flexibility that the 
AppendIf... commands within editfiles gives us, but as an insert, so 
that they can be specified in an exact place.

I am modifying shorewall config files which require a final line that 
says "THIS IS THE LAST LINE". I need to place all my edits above this 
line, and ideally what I would do is to use InsertFromFileIfNoSuchLines, 
or an InsertIfNoSuchLine "ThisLine" in a ForEachLineIn loop.

I could use the standard append commands, and then locate the "last" 
line, delete and then append it, but that isn't exactly tidy or 
necessarily reliable, as I would have to run it in a separate loop under 
a separate class defined by first loop.

The only other way I can think of doing it is to nest a group and a group:

        {
        /file-to-be-edited
                ForEachLineIn "data-file"
                        BeginGroupIfNoSuchLine "ThisLine"
                                EmptyEntireFilePlease
                                Append "# File Header & Comments"
                                InsertFile "datafile"
                                Append "# THIS IS THE LAST LINE"
                        EndGroup
                EndLoop
                DefineClasses "restart_shorewall"
                }

Since the first none match would cause the whole file to be re-written, 
subsequent lines would always find a match, but I would guess there are 
two problems with this:

1) ThisLine might not be a valid variable for BeginGroupIfNoSuchLine
2) ForEachLineIn doesn't allow nested loops, so does it allow a nested 
group?

If the above code works (by the way does ThisLine need " or '' or ``? 
The manual is a little unclear), then all well and good, but if not, I 
am going to have to work out another way of doing it. There is an 
INCLUDE option within shorewall that may allow me to have a much simpler 
file to edit, but having an InsertIf.. set of commands may be a worthy 
addition to CFEngine. Just don't ask me to write it, I wouldn't know 
where to start. ;)

Regards,

Marco van Beek