Ubuntu Wiki

Ubuntu Open Week - Screen-Profiles - DustinKirkland - Mon, Apr 27th, 2009

UTC -4

(02:01:44 PM) kirkland: jcastro: thank you Mr. Castro
(02:01:52 PM) kirkland: alrighty .... screen-profiles!
(02:02:12 PM) kirkland: so i'm going to divide this track up into a couple of small sets
(02:02:17 PM) kirkland: set 1 is a brief intro
(02:02:18 PM) Gordon- left the room.
(02:02:24 PM) kirkland: set 2 is a shared session demo
(02:02:40 PM) kirkland: and in set 3, you'll play with this on your own systems
(02:02:50 PM) kirkland: okay ... set 1
(02:02:57 PM) kirkland: GNU screen is a text-based window manager
(02:03:22 PM) kirkland: the Ubuntu server differs from several other server distributions in that it does not install a graphical desktop by default
(02:03:31 PM) kirkland: we try to keep our server very lean and mean!
(02:03:45 PM) kirkland: however, many people ask us why don't we ship a graphical desktop
(02:03:57 PM) ewsubach left the room ("has left the building.").
(02:04:02 PM) kirkland: in many cases, i actually believe that a *window manager* is actually what people want/need
(02:04:04 PM) jcastro: .oO (You can listen to Dustin's interview about screen profiles on http://ubuntupodcast.net/) -ed.
(02:04:39 PM) kirkland: a window manager gives you the ability to run multiple programs at the same time, in parallel, attach, detach, monitor system status, etc.
(02:04:53 PM) kirkland: screen has been around for 20+ years
(02:05:07 PM) kirkland: but in the default configuration, it's exceedingly difficult to customize
(02:05:30 PM) kirkland: so, for Ubuntu, we've created a phenomenal little program call screen-profiles that makes screen even more useful and user-friendly
(02:05:39 PM) kirkland: okay, so now for our demo ....
(02:05:46 PM) kirkland: so set 2, group demo!
(02:06:01 PM) kirkland: for this, you'll want to keep IRC open, where I'll explain what I'm doing
(02:06:18 PM) kirkland: but you'll also want to open up a terminal window, and ssh to this system ....
(02:06:30 PM) kirkland: ssh guest@guest@ec2-67-202-41-73.compute-1.amazonaws.com
(02:06:45 PM) kirkland: that's an instance of Ubuntu Jaunty running in Amazon's ec2
(02:06:50 PM) kirkland: the password is "guest"
(02:07:11 PM) kirkland: i'm going to give 60 seconds here for people to login
(02:07:38 PM) jcastro: .oO (the ssh url and password are in the topic if you need to refer to them)
(02:07:44 PM) kirkland: so what you're looking at is a shared screen session
(02:07:53 PM) kirkland: i have write access, and everyone else has read-only access
(02:08:05 PM) kirkland: for demo purposes, of course
(02:08:16 PM) kirkland: you should see across the bottom of your terminal two light grey lights
(02:08:19 PM) kirkland: lines
(02:08:27 PM) kirkland: the top line says:
(02:08:32 PM) kirkland: 0*&$ shell(guest)                                                      Menu:<F9>
(02:08:39 PM) kirkland: we currently have one window open
(02:08:43 PM) kirkland: (that's going to change in a moment)
(02:08:46 PM) kirkland: the second line says:
(02:08:51 PM) kirkland: \o/ Ubuntu 9.04                  2! 20# 0.57 2.6GHz 1.6GB,6% 2009-04-27 18:07:48
(02:08:57 PM) kirkland: i'm going to explain those shortly
(02:09:10 PM) kirkland: first, i'm going to launch the F9:Menu
(02:09:16 PM) kirkland: and I want to show you the help menu
(02:09:26 PM) kirkland: in your terminal, press F4
(02:09:36 PM) jcastro: kirkland: seems like some people can't get in, maybe there's a client limit?
(02:09:36 PM) kirkland: this will move your view over to the 2nd window I created
(02:09:49 PM) jcastro: but keep going
(02:09:50 PM) kirkland: jcastro: hmm, we have 25 people in
(02:09:58 PM) kirkland: 28+ and counting
(02:10:01 PM) jcastro: ok good
(02:10:23 PM) jcastro: continue, sorry
(02:10:27 PM) kirkland: anyone who can't see this in the ec2 instance, please run 'screen' locally
(02:10:32 PM) kirkland: (which will be set 3)
(02:10:49 PM) kirkland: okay, if you're in the screen session, please hit F4 to navigate to your 2nd window
(02:10:53 PM) kirkland: this is sort of like alt-tab
(02:11:57 PM) kirkland: okay, now, i've launched the help memu
(02:11:58 PM) kirkland: menu
(02:12:11 PM) kirkland: here, you can see that there are a couple of special actions bound to your F-keys
(02:12:18 PM) kirkland: in our shared screen session, i've disabled them
(02:12:50 PM) kirkland: but if you run 'screen' on your local jaunty system, (and choose the light profile) you should be able to use them
(02:12:56 PM) kirkland: so f2 will create a new window
(02:13:05 PM) kirkland: f3/f4 will go back and forth among open windows
(02:13:18 PM) kirkland: f5 will reload the profile (will demo in a moment)
(02:13:22 PM) kirkland: f6 will detach
(02:13:29 PM) kirkland: f7 will enter scrollback/search mode
(02:13:37 PM) kirkland: f9 will launch this menu
(02:13:49 PM) kirkland: and f12 will lock the screen (like a screensaver for the terminal)
(02:13:55 PM) kirkland: okay
(02:14:10 PM) kirkland: so another thing i can do from this menu is change my profile
(02:14:20 PM) kirkland: i have created a dozen or so different colored profiles
(02:14:27 PM) kirkland: i like a different color profile on each of my servers
(02:14:38 PM) kirkland: we're currently using the light profile
(02:14:48 PM) kirkland: i'm going to change it to a different one, then hit F5 to reload
(02:15:01 PM) sean is now known as Guest76893
(02:15:32 PM) kirkland: (this is somewhat laggy)
(02:15:42 PM) kirkland: (my apologies for that)
(02:16:26 PM) kirkland: okay, profile reloaded
(02:16:30 PM) kirkland: now it's white on black
(02:16:49 PM) kirkland: as you can see, there are other colors available, please play with them on your local setup later
(02:17:06 PM) kirkland: now, let's take a look at the bottom bar
(02:17:16 PM) kirkland: that's our status indicator
(02:17:34 PM) kirkland: \o/ is intended to be an approximation of the ubuntu logo (3 colors)
(02:17:44 PM) kirkland: followed by our current distro and release version
(02:17:59 PM) kirkland: the 2! indicates that there are 2 updates available
(02:18:12 PM) kirkland: 41# tells me that there are 41 user logged on :-)
(02:18:15 PM) kirkland: woohoo!
(02:18:25 PM) kirkland: the current load is 2.14 (changing every 2 seconds)
(02:18:35 PM) kirkland: this system has a single cpu, running at 2.6GHz
(02:18:50 PM) kirkland: but this also changes every 2 seconds, which is useful if you have cpu frequency scaling available
(02:18:57 PM) kirkland: there's 1.6GB of memory, of which 10% is used
(02:19:04 PM) kirkland: and of course, the current date and time
(02:19:17 PM) kirkland: but this is only a small subset of the status items you can enable
(02:19:31 PM) kirkland: this is intended to mimic gnome's applets in your gnome-panel
(02:19:50 PM) kirkland: so now i'm going to toggle some status notifications
(02:20:02 PM) kirkland: arch is the architecture of the system
(02:20:12 PM) kirkland: the battery is useful on laptops (not in ec2, though!)
(02:20:22 PM) kirkland: however, ec2-cost is very useful here!
(02:20:33 PM) kirkland: so i'm going to enable that
(02:20:38 PM) kirkland: as well as the hostname
(02:20:53 PM) kirkland: network bandwidth might be interesting on this system
(02:20:57 PM) kirkland: since so many of us are logged in
(02:21:27 PM) kirkland: also, note that there's a reboot-required icon that would popup if a system updated required
(02:21:30 PM) kirkland: a reboot
(02:21:38 PM) kirkland: this would look like this (@)
(02:21:50 PM) kirkland: so now I'm going to apply these, and refresh my profile
(02:22:23 PM) kirkland: (this operation apparently takes a minute when there's 44 of you connected!)
(02:22:37 PM) kirkland: okay, now we can see that this system has been up for 2 hours and 32 minutes
(02:22:49 PM) kirkland: and my current bill to ec2 is $0.31 :-)
(02:22:58 PM) kirkland: money well spent, sabfl ;-)
(02:23:03 PM) kirkland: sabdfl, rather
(02:23:22 PM) kirkland: there's a few more options here, that i'm going to skip
(02:23:26 PM) kirkland: but the last one is interesting
(02:23:32 PM) kirkland: "Install screen by default at login"
(02:23:41 PM) kirkland: this is what I did with your guest account before you logged in
(02:23:55 PM) kirkland: this is why you jumped immediately into this screen session, when you logged in
(02:24:05 PM) kirkland: in fact, i enable this feature on *all* of my server
(02:24:23 PM) kirkland: jcastro: okay, i'm going to pause now for questions
(02:24:32 PM) kirkland: jcastro: you want to paste them here?
(02:24:34 PM) jcastro: ok
(02:24:36 PM) jcastro: yep, one sec
(02:24:49 PM) jcastro: QUESTION: Why doesn't the marketing department highlight supercool features like screen profiles for the server? Instead they say it would "further improve infrastructure management efficiencies" (buzzword bingo)
(02:25:09 PM) kirkland: jcastro: hah :-)
(02:25:19 PM) kirkland: jcastro: well, i accept the compliment, screen-profiles is awesome!
(02:25:33 PM) kirkland: jcastro: and i hope that you, the community, can help spread the good word
(02:25:48 PM) kirkland: jcastro: i'm hoping for karmic that screen-profiles is used ubiquitously on the sever
(02:25:55 PM) jcastro: <peplin> QUESTION: What's the proper way to modify screen-profiles settings? I have a screenrc that I would like to use in combination with the profiles, but there doesn't seem to be an easy way to get rid of the top hardstatus line.
(02:26:06 PM) kirkland: jcastro: that it becomes as important to the Ubuntu server as Gnome/KDE are to Ubuntu/Kubuntu
(02:26:43 PM) kirkland: peplin: well, screen-profiles sources your local ~/.screenrc last
(02:27:11 PM) kirkland: peplin: does it not accept overrides of that hardstatus line?
(02:27:38 PM) peplin: I can override the bottom hardstatus, but seemingly not the line above that
(02:27:41 PM) kirkland: peplin: if not, i can add a feature to screen-profiles that would allow you to disable/enable the window list and/or the status line\
(02:28:03 PM) kirkland: peplin: please open a bug ;-)  i'll try to get that fixed for karmic
(02:28:04 PM) jcastro: <qense> QUESTION: Some programs also use the F* keys. How does that work? Currently screen catches them first and they aren't processed by the program
(02:28:45 PM) kirkland: qense: correct.  you can disable screen-profiles keybindings
(02:28:54 PM) kirkland: everyone, back over to the shared screen session
(02:29:10 PM) kirkland: see "Change keybinding set"
(02:29:30 PM) kirkland: you can accept the 'common' set of keybindings (f-keys), or take none of them
(02:29:50 PM) kirkland: in which case you'd need to use the bindings that screen provides, rather than our shortcuts
(02:29:55 PM) kirkland: note that i did *not* use:
(02:30:15 PM) kirkland: f1 -> help in gnome terminal, f10 -> menu, or f11 -> fullscreen
(02:30:24 PM) kirkland: so as not to conflict with gnome-terminal
(02:30:54 PM) kirkland: jcastro: any more q's?
(02:30:58 PM) jcastro: https://launchpad.net/~screen-profiles/+archive/ppa
(02:31:07 PM) kirkland: jcastro: ah, great point ....
(02:31:09 PM) jcastro: I wanted to mention where people can get it for older versions  of Ubuntu
(02:31:23 PM) jcastro: <qense> QUESTION: So actually GNU Screen is a shell wrapper giving you tabs and status indicators?
(02:31:27 PM) kirkland: right, so screen-profiles is packaged and in main for Jaunty
(02:31:51 PM) kirkland: however, i am providing packages for Hardy and Intrepid machines in a PPA
(02:32:01 PM) kirkland: I will, perhaps, try to get it into the backports archive
(02:32:13 PM) kirkland: but for now, you can use the the PPA very well
(02:32:28 PM) kirkland: qense: sort of ...
(02:32:36 PM) kirkland: qense: GNU screen is a "window manager"
(02:32:48 PM) kirkland: qense: that has a 50+ page manpage
(02:32:56 PM) kirkland: qense: really flexible, but complicated to setup
(02:33:23 PM) kirkland: qense: screen--profiles is sort of a best practices configuration for screen, packaged and made easy for Ubuntu\
(02:33:28 PM) jcastro: <tm> QUESTION: Should I be seeing any sort of lag with screen-profiles on vs off?
(02:33:36 PM) jcastro: <tm> I'm noticing the clock will pause and then jump ahead.  Text input is slower than with stock screen
(02:33:57 PM) kirkland: tm: on your local instance, or on the ec2 shared screen?
(02:34:04 PM) kirkland: tm: or on some other server you have access to?
(02:34:06 PM) jcastro: his linode
(02:34:10 PM) tm: ^^
(02:34:30 PM) tm: I understand there's going to be some hit, but it seems quite noticeable
(02:34:30 PM) kirkland: tm: there's actually a bug fix for that in jaunty-proposed;  should make it to jaunty-updates any day now
(02:34:34 PM) tm: cool
(02:34:43 PM) kirkland: tm: i think it should be fixed in jaunty-updates
(02:34:51 PM) jcastro: service with a smile!
(02:34:54 PM) jcastro: <HoellP> QUESTION: How do I send F* keys to the remote screen session i'm viewing in my local session?
(02:35:03 PM) kirkland: tm: basically, i had ionice/cpunice'd screen-profiles to the point at which there was lag;  i've disabled this in the update
(02:35:21 PM) tm: ah
(02:35:25 PM) tm: thanks!
(02:35:28 PM) kirkland: HoellP: screen within screen?
(02:35:39 PM) HoellP: yes...
(02:35:49 PM) kirkland: HoellP: don't :-)  or, if you figure out how, tell me :-)
(02:36:05 PM) kirkland: so to better answer HoellP's question, i do my screening like this ...
(02:36:17 PM) kirkland: i open one gnome-terminal tab per server I connect to
(02:36:27 PM) kirkland: so one ssh-session per gnome-terminal tab
(02:36:40 PM) kirkland: and then in each ssh/tab, I run screen, with multiple windows per server
(02:37:39 PM) kirkland: jcastro: okay, i'll move on to set 3 ...
(02:37:46 PM) kirkland: jcastro: and take a few more questions after
(02:37:56 PM) jcastro: sure!
(02:38:02 PM) kirkland: so, ladies and gents ... let's try this on your own system
(02:38:11 PM) kirkland: if you're running jaunty, you can just run 'screen'
(02:38:20 PM) kirkland: if you're not, head over to the PPA that jcastro pasted
(02:38:31 PM) kirkland: and install screen-profiles from there
(02:38:33 PM) jcastro: https://launchpad.net/~screen-profiles/+archive/ppa
(02:38:50 PM) kirkland: (note that the screen-profiles from that PPA is newer than the one in Jaunty, and as such includes *even more* features)
(02:39:18 PM) kirkland: once the screen-profiles package is installed, run 'screen'
(02:39:28 PM) kirkland: the first time you run it, it should prompt you to select a profile
(02:39:37 PM) kirkland: the 'plain' profile is actually not a screen profile
(02:39:47 PM) kirkland: rather, this is the system default /etc/screenrc
(02:39:59 PM) kirkland: very boring, includes *none* of the features i've been discussing
(02:40:12 PM) kirkland: as such, upstream, i've renamed this NONE instead of plain
(02:40:25 PM) kirkland: the screen-profiles package just comes with light, dark, and black
(02:40:29 PM) kirkland: 3 very simple profiles
(02:40:39 PM) kirkland: install screen-profiles-extras for about a dozen other colors
(02:40:54 PM) kirkland: so choose, one of those profiles, and now you're in screen
(02:41:02 PM) kirkland: play with the F-keys
(02:41:10 PM) kirkland: hit F2 to open a new window
(02:41:20 PM) kirkland: run something in that window, maybe "top"
(02:41:35 PM) kirkland: hit f3/f4 to switch back and forth between your windows
(02:41:45 PM) kirkland: now, let's detach, and reattach
(02:41:48 PM) kirkland: hit F6
(02:42:01 PM) kirkland: that'll detach, but your program (top, etc) will still be running the background
(02:42:12 PM) kirkland: i use this *all the time* when I'm doing something like a big wget, or rsync
(02:42:19 PM) kirkland: now, reattach with "screen -r"
(02:42:25 PM) kirkland: you should be back in your screen session
(02:42:36 PM) kirkland: now, let's try scrollback mode
(02:42:47 PM) kirkland: (i'll demo this in the ec2 session for anyone not doign this locall)
(02:43:09 PM) kirkland: if you're in the ec2 session, go to the leftmost window
(02:43:17 PM) kirkland: if you're doing this locally, hit F7
(02:43:32 PM) kirkland: this will put you in a vi-like mode scrolling and searching
(02:43:50 PM) kirkland: you can type terms and search just like vi
(02:44:07 PM) kirkland: also, this is per-window
(02:44:25 PM) kirkland: so if you hit f4, and go to your next window, and enter scrollback, you're scrolling for that window
(02:44:41 PM) kirkland: also, try F9
(02:44:56 PM) kirkland: you can adjust your screen-profile's colors
(02:45:00 PM) kirkland: toggle status notifications
(02:45:03 PM) kirkland: install screen by default
(02:45:12 PM) kirkland: or uninstall screen by default at login
(02:45:17 PM) kirkland: if you do enable that
(02:45:23 PM) kirkland: detach (F6)
(02:45:25 PM) kirkland: then ssh localhost
(02:45:34 PM) kirkland: such that you login
(02:45:51 PM) kirkland: you should see screen launch by default, re-attaching to your most recent screen session
(02:46:12 PM) kirkland: jcastro: i'll pause again for questions ... wanna paste a few here?
(02:46:43 PM) jcastro: <haliner> QUESTION: How do you set up the read-only session?
(02:46:50 PM) jcastro: popular question. :p
(02:46:55 PM) kirkland: haliner: ah :-)
(02:46:59 PM) kirkland: that's a complicated one
(02:47:04 PM) kirkland: let me get you a url ...
(02:47:13 PM) kirkland: http://www.linux.com/feature/56443
(02:47:14 PM) jcastro: we can perhaps blog that later or something
(02:47:22 PM) jcastro: I am sure lots of people can think of creative ways to use this
(02:47:25 PM) kirkland: basically, you have to make /usr/bin/screen.real setuid
(02:47:31 PM) jcastro: <gQuigs> QUESTION: just closing gnome-terminal keeps screen open and running.. doing that won't break anything right?
(02:47:31 PM) kirkland: then play with screen's acl's
(02:47:39 PM) jcastro: <gQuigs> aka.. do we really need to manually detach
(02:47:58 PM) kirkland: see http://manpages.ubuntu.com/manpages/jaunty/en/man1/screen.1.html, chacl
(02:48:24 PM) kirkland: gQuigs: right
(02:48:35 PM) kirkland: gQuigs: you can manually detach, if that's what you explicitly want to do
(02:48:53 PM) kirkland: in fact, as you "leave" the ec2 shared screen session, that's probably the only way you can do it
(02:48:53 PM) jcastro: <ktenney> does scrollback offer selection, yank, paste ...
(02:49:00 PM) kirkland: ktenney: yes!
(02:49:26 PM) kirkland: ktenney: see "copy" mode in http://manpages.ubuntu.com/manpages/jaunty/en/man1/screen.1.html
(02:49:43 PM) kirkland: ktenney: F7 is just a keybinding that puts you straight into copy/scrollback mode
(02:50:13 PM) kirkland: jcastro: any other pending questions?
(02:50:42 PM) jcastro: nope, continue
(02:50:48 PM) kirkland: jcastro: cool
(02:50:54 PM) jcastro: but BugeyeD say: can 'leave' by disconnecting via ssh as well: <enter>~.
(02:50:57 PM) kirkland: okay ... last feature i'm going to go over
(02:51:04 PM) kirkland: jcastro: BugeyeD: cool, thanks.
(02:51:23 PM) kirkland: so siretart has packaged screen-profiles for debian
(02:51:36 PM) kirkland: and i've heard mumblings that others are working on it for other distros too
(02:51:52 PM) kirkland: but people have asked me quite a bit about screen-profiles on other linux systems
(02:51:56 PM) jcastro: james wilcox has put it in opensuse
(02:52:03 PM) kirkland: jcastro: righto
(02:52:20 PM) kirkland: but what about ubuntu systems, where you don't have admin access, but you want to run screen-profiles?
(02:52:21 PM) kirkland: aha!
(02:52:26 PM) kirkland: screen-profiles-export
(02:52:42 PM) kirkland: from a system where you do have screen-profiles, you can run the screen-profiles-export command
(02:53:05 PM) kirkland: this will create a tarball that you can unzip on almost any linux system that has screen installed
(02:53:15 PM) kirkland: and you'll get about 90% of screen-profiles functionality
(02:53:21 PM) kirkland: you won't get the F9 menu command
(02:53:30 PM) kirkland: (the python-newt deps aren't everywhere)
(02:53:38 PM) kirkland: but you can cd ~/.screen-profiles
(02:53:49 PM) kirkland: and manually edit the mostly-intuitive configuration files there
(02:54:13 PM) kirkland: such as ~/.screen-profiles/status
(02:54:26 PM) kirkland: that's how you turn on/off the status notifications in the bottom window
(02:55:09 PM) kirkland: so that's about all i have to say
(02:55:14 PM) jcastro: woo!
(02:55:21 PM) kirkland: i have some new features planned for karmic
(02:55:25 PM) dresi: hi!
(02:55:33 PM) kirkland: or, if you use the screen-profiles PPA, you'll get this sooner ;-)
(02:55:41 PM) dresi: i am from spain. Any person talnking in spanish?
(02:55:51 PM) jcastro: dresi: #ubuntu-classroom-chat please
(02:55:55 PM) dresi: ok
(02:56:08 PM) kirkland: i'll take any other questions at this point
(02:56:16 PM) kirkland: or turn it over to jcastro ;-)
(02:56:30 PM) jcastro: ok, thanks dustin!
(02:56:36 PM) jcastro: what's your blog so we can follow along?
(02:56:48 PM) kirkland: jcastro: :-)  http://blog.dustinkirkland.com
(02:57:10 PM) kirkland: i will be booting everyone off of ec2 now :-)
(02:57:14 PM) Veeyawn: Thanks Dustin
(02:57:23 PM) thegrieve:  /me cheers
(02:57:24 PM) somnoliento: This was awesome! thanks!
(02:57:25 PM) thegrieve: hehe
(02:57:34 PM) thegrieve: thanks alot
(02:57:37 PM) JFo: screen is my new favorite thing
(02:57:41 PM) JFo: thanks kirkland
(02:58:20 PM) kirkland: ||^o
(02:58:29 PM) ***kirkland takes a bow
(02:58:57 PM) ***gQuigs claps
(02:59:14 PM) kirkland: #screen-profiles if you want to discuss further, with other members of the screen-profiles community
(03:00:13 PM) jcastro: kirkland: what was the final cost of the demo?
(03:00:23 PM) jcastro: according to the applet?
(03:00:25 PM) kirkland: jcastro: $0.42
(03:00:28 PM) kirkland: (appropriate)