iwatch
is a program to watch the given command's output periodically
and watch the output change.
% git clone https://github.com/iij/iwatch
% cd iwatch
% ./configure
% gmake
% su
# gmake install
Please remark to use "gmake" to use GNUmakefile. Makefile is for OpenBSD.
For OpenBSD
% git clone https://github.com/iij/iwatch
% cd iwatch
% make
% su
# make BINDIR=/usr/local/bin MANDIR=/usr/local/man/man install
% iwatch -e netstat -s