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View the status of a long emerge

Ryan — Wed, 31 Dec 2008 14:13:29 +0000

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

Install Java browser plugin in Gentoo

Ryan — Sun, 02 Nov 2008 22:05:57 +0000

To run Java code on a Gentoo system you must have a JRE (Java Runtime Environment) installed. The JRE will install a 32-bit browser plugin, among other things, which is necessary to take advantage of Java applets in Firefox.

Before we go any further, it must be noted that this will only work with the 32-bit version of Firefox. This is because the binary JRE package is only distributed in 32-bit and is therefore incompatible with the 64-bit version of Firefox. If you run a 64-bit system make sure that you have emerged the www-client/mozilla-firefox-bin package to get the 32-bit browser.

There are numerous JRE packages within portage, but the recommended package to emerge is dev-java/sun-jre-bin. Don’t confuse the JRE with JDK (Java Development Kit) which will add unnecessary Java programming tools to the installation.

To get the browser plugin you must enable the nsplugin USE flag when emerging the JRE. You can add this to your global USE flags by placing it directly into the make.conf file.

If you don’t want every package capable of installing a plugin to do so, you can limit the flag to this package only by adding the following entry to /etc/portage/package.use.

dev-java/sun-jre-bin nsplugin

Once the nsplugin flag is set to your liking then go ahead and emerge the JRE.

# emerge -av dev-java/sun-jre-bin

The ‘-v‘ and ‘-a‘ options will allow you view the USE flags that are enabled, and confirm they are correct before allowing it to continue.

If you are running an amd64 system then you will need to emerge the app-emulation/emul-linux-x86-java package as well. This package contains the basic 32-bit libraries needed to run the 32-bit JRE binaries on your 64-bit system.

You will need the nsplugin USE flag enabled for this package as well. If you didn’t add the keyword to your global USE flags in the previous step, add the following entry to /etc/portage/package.use.

app-emulation/emul-linux-x86-java nsplugin

Now emerge the package, again making sure the USE flags are correct.

# emerge -av app-emulation/emul-linux-x86-java

You will now have to configure your system to use the JRE with the eselect command utility.

Use this for a x86 system.

# eselect java-nsplugin set sun-jre-bin-1.6

Use this for an amd64 system.

# eselect java-nsplugin set 32bit emul-linux-x86-java-1.6

Once all of these steps have been completed you can verify that everything is correct by running.

# eselect java-nsplugin list

Available 32-bit Java browser plugins
  [1]   emul-linux-x86-java-1.6  current
Available 64-bit Java browser plugins

Check that Firefox has found the plugin by opening up a new window and entering about:plugins in the address bar. You should now see the Java plugin listed.

Update your entire Gentoo Linux system

Ryan — Fri, 10 Oct 2008 12:42:55 +0000

Gentoo Portage makes it fairly easy to update all the installed packages on your system. The emerge and revdep-rebuild tools are powerful and make the process of recompiling everything much less painful than it sounds.

The emerge and revdep-rebuild commands require root privileges so switch to root or use sudo.

The first step is to synchronize your Portage tree with the latest mirror. This command will get you information on the latest packages that are currently available.

# emerge --sync

Perform an “pretend” emerge to see what packages will be updated and installed on your system.

# emerge -uDNvp world

These are the packages that would be merged, in order:

Calculating world dependencies... done!
[ebuild     U ] dev-util/pkgconfig-0.23 [0.22] USE="-hardened" 1,009 kB
[ebuild     U ] media-sound/wavpack-4.50.1 [4.41.0] USE="mmx" 367 kB
[ebuild     U ] dev-libs/gmp-4.2.2-r2 [4.2.2] USE="-doc -nocxx" 0 kB
.
.
.
[ebuild  N    ] sys-apps/man-pages-posix-2003a  949 kB 

Total: 149 packages (100 upgrades, 36 new, 2 in new slots, 11 reinstalls), Size of downloads: 354,800 kB

Lets go over these options.

-u update packages
-D consider entire dependency tree for all packages
-N include packages with USE flag changes
-v verbose emerge output
-p pretend to do the emerge

The ‘world‘ argument tells emerge to use the list of packages in your world file. This list contains all packages that have been directly emerged on your system. These packages do not include dependences or packages that were emerged using the ‘–oneshot‘ option. Your world file is located here /var/lib/portage/world.

The output of this command will tell you one of two things. Either everything is good and you can go ahead and perform the update, or Portage has found some conflicts such as blocking packages that must be fixed before you continue. Hopefully the former is the case, but if there are conflicts Portage messages will usually point you in the right direction.

Before performing the actual update you can use the parallel-fetch feature to speed up the package downloads and shorten the update process. To do this add the following line to /etc/make.conf.

FEATURES="parallel-fetch"

If there are no Portage issues, you have reviewed the list of packages to be installed and everything looks correct, then you can start the update. To perform the update run the same command as before but remove the ‘-p‘ option.

# emerge -uDNv world

Occasionally a system update will break shared library dependencies as an upgraded package may no longer be compatible with packages which use it. Enter the revdep-rebuild reverse dependency re-builder tool.

The revdep-rebuild tool is part of the gentoolkit package which you must emerge first.

Run this command after a large system update to ensure all packages are in good shape.

# revdep-rebuild

This command will scan your system for missing shared library dependencies and fix them by re-emerging those missing packages.

Speed up Gentoo emerge with “parallel-fetch”

Ryan — Mon, 29 Sep 2008 00:03:03 +0000

By default when you emerge a long list of packages in Gentoo you have to download each package completely before the build process can begin. This can be a large bottleneck, especially if your internet connection is not very fast.

Luckily Portage has a great solution.

Go to the file /etc/make.conf and add “parallel-fetch” to the FEATURES variable like this.

FEATURES="parallel-fetch"

If the FEATURE variable already exists add “parallel-fetch” to the end separated by whitespace.

FEATURES="sandbox parallel-fetch"

From now on Portage will fetch the source files for the next package in the list even while it is compiling another package.

To see parallel fetch progress, run this command.

$ tail -f /var/log/emerge-fetch.log