Listing 2: The example library filter.lib

# example library called filter.lib
# comments start in the first column
#
# include sys0.lib found somewhere on the search path
include sys0.lib
fold        fold @@
relocperl   sed 's?^#! */usr/bin/perl?#!/usr/lbin/perl?' @@
lower       cat @@ | tr '[:upper:]' '[:lower:]'
upper       cat @@ | tr '[:lower:]' '[:upper:]'
prep4tex    awk -f clear.awk @@ | \
awk -f quote.awk | sed -f txt2tex.sed

# End of File