At certain times while using Gentoo you are going to have to perform a large emerge, for example when you do an update world. It can be challenging to keep track of the status of this emerge with all the output flying by on the screen. It can also become a problem if you want to check on the status from another machine that did not initiate the emerge.
Thankfully you can check the /var/log/emerge.log and get the current status.
Run this command to see the last 10 lines of the log.
$ sudo tail /var/log/emerge.log
You can combine this command with watch and get real-time updates. This command will automatically update every second.
$ watch -n 1 "sudo tail /var/log/emerge.log"
Likewise you can use the ‘-f‘ tail option to get updates.
$ sudo tail -f /var/log/emerge.log