To do this using the exiftool command-line interface, you will
also need a helper application that does the string manipulations
for you. In Unix, "sed" will do this. There is likely some Windows
utility that will allow you to substitute strings on the command
line, but I can't help you there.
Once you find the utility, the translations can be done like this:
exiftool -caption-abstract -b a.jpg | subst kid child - | exiftool -caption-abstract"<=-" a.jpg
Here, the "subst kid child -" command will change depending on the
utility you use to do the substitution.
An alternative is to do this in Perl using the ExifTool API, which is actually
very simple, but for this you need to know a bit of Perl and have the
Perl interpreter installed.
- Phil