barcat -t-1 -ftime='\K' input/ping.txt ?
PING google.com(ams15s40-in-x0e.1e100.net (2a00:1450:400e:80d::200e)) 56 data bytes
... icmp_seq=1 time=9.92 ms ---------+
-... icmp_seq=2 time=9.38 ms --------+
+... icmp_seq=2 time=9.38 ms ---------
-------- +
-... icmp_seq=3 time=10.5 ms --------+-
+... icmp_seq=3 time=10.5 ms --------+>
... icmp_seq=4 time=9.90 ms --------+
... icmp_seq=5 time=9.66 ms --------+
... icmp_seq=6 time=9.88 ms --------+
... icmp_seq=7 time=9.44 ms --------+
------- +
-... icmp_seq=8 time=11.8 ms -------+--
+... icmp_seq=8 time=11.8 ms -------+=-
... icmp_seq=9 time=9.56 ms -------+
... icmp_seq=10 time=10.0 ms -------+
... icmp_seq=11 time=9.48 ms -------+