grep whole file and tail it without using "line-buffered" option in grep

Question

I have BusyBox v1.21.0 installed and it has got very basic grep operation, no --line-buffered option

grep sync_complete /var/log/messages
tail -f /var/log/messages | grep sync_complete

is it possible to combine above commands into single line command? thanks!

Answer 1

Use -n +1 to make tail read the file from the start:

tail -n +1 -f /var/log/messages | grep sync_complete