Emerge

1. # emerge –resume

   Think of a scenario when you have to reboot or shutdown while stilling emerging. You can just Ctrl+C to interrupt the emerging process. Later on when entering the system, run this command before any other emerge-related commands. This will save you a lot of time especially you have a long emerge list. For example, you are in the last one of 100 packages. This command will only continue to emerge the last package.

2. Verbose mode (-v)

   --verbose [ y | n ] (-v short option)
   Tell  emerge to run in verbose mode.  Currently this flag causes
   emerge to print out GNU info errors, if any, and to show the USE
   flags  that  will  be used for each package when pretending. The
   following symbols are affixed to USE flags in order to  indicate
   their status:
   
   
   Symbol   Location    Meaning
   ──────────────────────────────────────────────────────────────
   
   -        prefix      not enabled (either disabled or removed)
   *        suffix      transition to or from the enabled state
   %        suffix      newly added or removed
   ()       circumfix   forced, masked, or removed
   {}       circumfix   state is bound to FEATURES settings
   

3. Manual download.

   Everytime emerging a package, the first thing emerge to do is downloading the package source code *.tar.gz, and puting it in /usr/portage/distfiles/.

   If the Internet is slow or command line http/https is blocked (Dropbox due to GFW), you can follow the download links from emerge message in terminal to get a copy of *.tar.gz to /usr/portage/distfiles/, and then emerge again.

4. World set

   1. Install a pkg

      --select=y -w: This is default action. Emerge a pkg and add to world file.

      --oneshot -1: Emerge as normal, but do not add the packages to the world file for later updating.

   2. Already installed

   --deselect=y: Remove atoms and/or sets from the world file. No installation is involved.

   --noreplace: Skips the packages specified on the command-line that have already been installed. One usage is add an installed pkg to world file.

   1. --noreplace has other usage like emerge -avtuDN --with-bdeps=y --noreplace firefox @world. This tells not to update firefox.