A common thing with flipflop is to want to exclude one or both endpoints. To do this, you need to actually check the scalar value returned by the .. operator; it will be a number beginning at 1 when the flip condition is met and increasing once each time thereafter, with an "E0" appended when the flop condition is met. (False is returned as "".)

Anyway, here are some examples. Better suggestions greatly encouraged.

$ cat data
initial
start
interior
end
final

$ # Include both endpoints
$ perl -wlne'print if /start/../end/' data
start
interior
end

$ # Exclude starting point
$ perl -wlne'print if ((/start/../end/) || 0) > 1' data
interior
end

$ # Regex alternative for exclude starting point
$ perl -wlne'print if (/start/../end/) =~ /^(?!1(?!\d))\d/' data
interior
end

$ # Exclude ending point
$ perl -wlne'print if (/start/../end/) =~ /^\d+$/' data
start
interior

$ # Exclude both endpoints
$ perl -wlne'print if (/start/../end/) =~ /^\d+(?<!^1)$/' data
interior

$ # or:
$ perl -wlne'print if (/start/../end/) !~ /^1?$|E/' data
interior
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