chromeos-crosh-custom-setup.md

Customize Chromebook Chrosh Shell Environment

Requirement: Chromebook, Common Sense, Commandline Ablity, 1 hour of time

Dear developers with a spare Chromebook lets inject a little personalization into your Crosh shell with custom fonts, the solarized theme, and extra secure shell options.

Also, keep in mind that the terms Chrosh, Chrosh Window, and Secure Shell all refer to various versions and extentions built around the ChromeOS terminal. Settings that affect the ChromeOS terminal are global.

Custom Fonts

If ChromeOS was a normal Linux distribution, adding fonts would be as easy as dropping a font file into the .fonts folder and changing a terminal setting. Sadly, we need to do a bit of work - some of it rather scary - to get custom fonts working with ChromeOS.

Mounting Root Filesystem as Read-Write

Chromebook must be in developer mode and have rootfs verification turned off so that the root read only file system can be remounted as read-write. Once this is done, extra fonts can be added to ChromeOS's font folder.

WARNING: Follow instructions very carefully. Failure to follow these instructions can result in a non-booting Chromebook. If you screw up you will need to restore your Chromebook to stock. You have been warned.

1. Fire up the Crosh shell with ctrl+alt+t

2. sudo /usr/share/vboot/bin/make_dev_ssd.sh --remove_rootfs_verification

3. The above command will fail and tell you to run with --partitions N flag at the end where N can be any number. Run the command again with the new flag (you should be able to copy-paste it from the output).

4. sudo crossystem dev_boot_signed_only=0

5. The above command turns the verification check off. Because of step 2, the Chromebook will fail to boot if the verificaiton check is on.

6. sudo mount -o remount,rw /

7. Check that your root filesystem remounted as read-write.

8. cat /proc/mounts | grep '\ \/\ '

9. Output should look something like this:

rootfs / rootfs rw 0 0 /dev/root / ext2 rw,relatime 0 0

10. If both entries have 'rw' like the above example, then it worked. Proceed to Step 11. Otherwise if either entry contains 'ro' instead of 'rw', you'll need to re-run step 2 with the suggested --partition N and --force arguments. Be sure to read the warning before you proceed.

11. Reboot your Chromebook.

Congrats. The dangerous part of the setup is done.

Font Folder Location and Font Install

Fonts in .ttf format can be installed to the folder /usr/share/fonts/croscore/

Installing either the normal or powerline patched versions of your favorite monospaced fonts to the aforementioned folder is required for proper configuration of the font family settings in Secure Shell a bit latter.

https://github.com/Lokaltog/powerline-fonts

I prefer the powerline patched version of Ubuntu Mono. Other mono space fonts - including Adobe's Source Code Pro - are great fonts for Crosh usage too!

Add Required Chrome Extentions

To further customize our Crosh window, install both Secure Shell and the Crosh Window extentions from the Chrome Web Store.

• Secure Shell
• Crosh Window

Sett Up Chrosh's Font-Family and Font-Size

ChromeOS apps menu > right click on the Secure Shell icon > select options

Change the terminal settings as you see fit. Pay special attention to:

font-family

Keep in mind ChromeOS will only load the first avaliable font that you specified in the font-family field's comma-separated list. If you wan to use a custom font make sure you add it as the first entry. To get the name of the font you want to use, refer to the 'Powerline Font Family' column in the table on this page. For example, if you want to use Ubuntu Mono, add "Ubuntu Mono derivative Powerline", to the front of the 'font-family' field.

font-size

Since most(possibly all) powerline fonts are slighly smaller than default font, you may wish to bump the size up from 15 to a modestly larger 16 or 17.

base16

Base16 is a wonderland of beauty for your terminal.

It's a bit tricky to set up properly on the Chromebook. This page has instructions on setting up base16 for Crosh and making the colors work with vim + tmux inside your chroot.

Solarized Color Theme

It's almost criminal how easy it is to install solarized for Crosh.

• Download a solarized prefs.js file. Two good options are:

  • giraj/solarized-crosh
  • johnbender/prefs.js

I'm including the code for the prefs.js file I used for convenience.

// Disable bold 
term_.prefs_.set('enable-bold', false) 

// Use this for Solarized Dark 
term_.prefs_.set('background-color', "#002b36");
term_.prefs_.set('foreground-color', "#839496");

// Solarized Colors
term_.prefs_.set('color-palette-overrides', [
  '#073642', 
  '#dc322f', 
  '#859900', 
  '#b58900', 
  '#268bd2', 
  '#d33682', 
  '#2aa198', 
  '#eee8d5', 
  '#002b36', 
  '#cb4b16', 
  '#586e75', 
  '#657b83', 
  '#839496', 
  '#6c71c4', 
  '#93a1a1', 
  '#fdf6e3'
]);

• Open the Chrome Javascript Console ctrl+shift+j
• Paste the contents of your solarized prefs.js file into the console
• Hit enter

Further Customizations

Loading a Crosh Window based Ubuntu 14.04 Chroot is the best way to make use of the customizations.

• dnschneid/crouton with sudo sh -e ~/Downloads/crouton -r trusty -t cli-extra

For powerline patched font use in vim:

• add bling/vim-airline to vim
• edit your .vimrc to include let g:airline_powerline_fonts = 1

For powerline patched font use in tmux:

• Install ZSH shell, oh-my-zsh, and set the zsh-theme to agnoster

Fin

Thanks for reading!