Martin, you are right - in this case, there's a simple way to avoid writing anything, since Augeas can just check whether the old and the new value for the tree node are different, and hence can figure out if anything needs to be written at all.
There are more complicated cases of a noop, like removing something from the tree and then recreating that part of the tree that are not covered by that simple check. For the record, what Augeas does is write the new file as file.augnew, and then compare with the original file byte-for-byte. If the two files are identical, file.augnew is simply removed. If there was a change, file.augnew is renamed. The rename requires that the .augnew and the original file reside on the same mountpoint, and the simplest way to ensure that is to create file.augnew in the same directory as the original one. To catch your use case in all generality, I could just write the changed file to a memstream, do the compare from that, and only write to .augnew when something has changed. David -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
