Emerge --sync

This updates the portage tree that is located in the directory that the PORTDIR variable refers to (default location is /usr/portage). The SYNC variable  specifies  the remote  URI  from  which files will be synchronized. The PORTAGE_SYNC_STALE variable configures warnings that are shown when emerge --sync has not been executed recently.

WARNING: The emerge --sync action will modify and/or delete files located inside the directory that  the  PORTDIR  variable refers to (default location is /usr/portage). For more information, see the PORTDIR documentation in the make.conf(5) man page.

NOTE: The emerge-webrsync program will download the entire portage tree as a tarball, which is much faster than emerge --sync for first time syncs.