I was watching this command run
tar cf - 20180412 -P | pv -s $(du -sb 20180412 | awk '{print $1}') | gzip > 20180412.tar.gz
9.02GiB 0:01:20 [ 114MiB/s] [===================================================================================================================================================================>] 100%
and wondered how can pv
work. I thought pipes were eager, but I think this pv
can only work right if the pipes are lazy.
So, are bash pipes lazy or eager?