Sunadmn, you're very kind,

The file is a bibliography file some of whose lines start /index while many others also have a / at the beginning.

My problem is to add a %-sign at the end of the /index lines.

I know that it might be simply done in Perl, I just have such little experience yet that trying to piece it together in the on-line manual has been rather a lengthy process.

Is this enough detail ?

TIA

sativa