9 ms·

All about GNU Screen

72 points by mace 16y ago

wallfly 16y ago
tmux is a great BSD-licensed alternative: http://tmux.sourceforge.net/ http://tmux.sourceforge.net/ I've tried both, and the licensing issue aside, I've found I prefer tmux. Anyway, not wanting to turn this into a gnu vs. bsd, tmux vs. screen argument, but I didn't eve know tmux existed until someone pointed me to it, so I'm just passing on the knowledge.
- mhansen 16y ago
  Can you elaborate on why you prefer tmux? Myself, I use byobu, a set of user-friendly wrapper scripts around screen.
  - w1ntermute 16y ago
    One of the big things is that it preserves split screen arrangements upon detachment. I SSH into a server and basically use Screen/tmux as my IDE, and losing my split screen setup when I detach is very annoying.
  - dschobel 16y ago
    Personally I appreciate the client-server design and the memory savings it lends when connecting multiple terminals to the same tmux session: http://www.linuxized.com/2010/05/switching-from-gnu-screen-to-tmux/ http://www.linuxized.com/2010/05/switching-from-gnu-screen-t... Plus the more liberal BSD license but that's more of an ideological issue.
  - mace 16y ago
    tmux has been recommended frequently lately, but I have not tried it. This seems to be decent summary of the differences between it and screen: http://unix.stackexchange.com/questions/549/tmux-vs-gnu-screen http://unix.stackexchange.com/questions/549/tmux-vs-gnu-scre...
  - carterschonwald 16y ago
    off hand from just playing with tmux for the past 20 minutes, it looks like tmux better abstracts its commands from how it internally tracks the windows and sessions than does screen. In particular, when i've played with screen, i found that i was frequently stymied by the broken abstraction of the way screen stored its state vs what I wanted to do. byobu sadly doesn't work on macbooks, but it looks cool!
    - carterschonwald 16y ago
      to further clarify: when choosing a session (and thus a collection of windows), in screen the process id info etc is exposed at the user level, which perhaps is useful to someone, but not for how use terminal and such. Thus because these things are not as directly exposed via the interaction model that tmux does, doing stuff becomes simpler and semantically clearer
  - petercooper 16y ago
    I did a short (free) screencast about tmux if you want a more visual run-through: http://peterc.org/blog/2010/216-tmux.html http://peterc.org/blog/2010/216-tmux.html
  - pyre 16y ago
    tmux was able to split windows vertically before screen was able to mostly due to politics, AFAIK.
- carterschonwald 16y ago
  thanks! this looks very interesting and worth looking into
- grump 16y ago
  I'm a fan of dtach + dvtm. tmux looks pretty great too.
adulau 16y ago
A nice function (not mentioned in this presentation) is the ability to send commands (-X) to a specific window in a screen session. This allows you to completely control GNU Screen the shell or another programming environment while benefiting from the persistent or logging of a session. screen -d -m -S mysession screen -S mysession -X screen -a -tjob1 'top' Using -X you can call the commands available within GNU Screen to control the session or the windows.
- pyre 16y ago
  The Gnu Screen command 'stuff' writes directly to the STDIN on the window. This is how the REPL integration setups with screen/vim that appear on HN from time to time work. e.g. screen -a window1 -X stuff 'import sys' would send 'import sys' to whatever app was reading STDIN on window1.
luu 16y ago
If you haven't heard of it, Xpra is sort of like screen for X, in that it lets you run persistent X sessions (rootlessly, unlike VNC). Shifter (http://shifter.devloop.org.uk/ http://shifter.devloop.org.uk/) packages screen and Xpra together with a nice user-friendly interface for Windows, OpenSolaris, BSD, Mac OS, Linux, etc., and it includes a patch for Xpra so that it works for Windows!
surki 16y ago
I strongly recommend having a look at the Gnu Screen customization in Ubuntu Server. http://blog.dustinkirkland.com/2008/12/ubuntu-server-includes-window-manager.html http://blog.dustinkirkland.com/2008/12/ubuntu-server-include...
- mhansen 16y ago
  That project has matured a lot, it's now called byobu. It's friggin' awesome. https://launchpad.net/byobu https://launchpad.net/byobu
moe 16y ago
I love screen. I use it on a daily basis for ~10 years. What still bothers me mightily is that, up to this day, nobody has bothered to get the history scrolling right (neither in tmux, btw). You still have to press an awkward key combination to switch to "copy mode", the normal mechanisms (PGUP, mousewheel, scrollbar) only result in garbage. I've tried various partial fixes ("altscreen off") but none works properly across sessions or with multiple windows. Years back I even tried to patch screen myself but had to surrender over the (for me) crufty code-base. And that despite the solution being fairly obvious: Just redraw the entire window while scrolling, just like irssi and plenty other console apps do it. And just like screen itself does it in copy-mode. I wish someone would finally take on this issue...
- bricestacey 16y ago
  You can scroll through the history of your terminal, but not of individual screens by adding this to your .screenrc file. termcapinfo xterm|xterm-color ti@:te@ Not 100% there, but does well for me.
  - moe 16y ago
    Yes I have that, it's the partial solution I mentioned. It unfortunately doesn't preserve the history during detach/reattach. And the history gets scrambled when you switch between windows.
beambot 16y ago
My biggest impediment to using screen is emacs key binding conflicts. I never took the time to determine an acceptable solution. Can an emacs guru share their solution...?
- graywh 16y ago
  I use ctrl-_ (aka ctrl-7) for screen/tmux commands. I don't its functionality in Vim. Not sure if it helps for Emacs.
- Estragon 16y ago
  Change the C-a binding to C-z.
- nagoff 16y ago
  I use backtick as the screen command, which is fine unless you write a lot of bash scripts. $ screen -e '``'
  - chrismealy 16y ago
    I'll give that a try ... I had to do screen -e '\`\`'
- gojomo 16y ago
  So many people hit this, and then use screen less, and everyone adopts a different alternative. I suspect a screen fork which simply adopts new standard emacs/bash-compatible defaults could eventually overtake the original in usage.
Locke 16y ago
I was just thinking today how wonderful it would be if my web browser let me navigate tabs with the same key bindings as screen. If I had a nickel for every time I've done "select all" when I wanted to quickly switch back to the last active tab.

72 points by mace 16y ago

tmux is a great BSD-licensed alternative: http://tmux.sourceforge.net/ http://tmux.sourceforge.net/ I've tried both, and the licensing issue aside, I've found I prefer tmux. Anyway, not wanting to turn this into a gnu vs. bsd, tmux vs. screen argument, but I didn't eve know tmux existed until someone pointed me to it, so I'm just passing on the knowledge.

mhansen 16y ago
Can you elaborate on why you prefer tmux? Myself, I use byobu, a set of user-friendly wrapper scripts around screen.
- w1ntermute 16y ago
  One of the big things is that it preserves split screen arrangements upon detachment. I SSH into a server and basically use Screen/tmux as my IDE, and losing my split screen setup when I detach is very annoying.
- dschobel 16y ago
  Personally I appreciate the client-server design and the memory savings it lends when connecting multiple terminals to the same tmux session: http://www.linuxized.com/2010/05/switching-from-gnu-screen-to-tmux/ http://www.linuxized.com/2010/05/switching-from-gnu-screen-t... Plus the more liberal BSD license but that's more of an ideological issue.
- mace 16y ago
  tmux has been recommended frequently lately, but I have not tried it. This seems to be decent summary of the differences between it and screen: http://unix.stackexchange.com/questions/549/tmux-vs-gnu-screen http://unix.stackexchange.com/questions/549/tmux-vs-gnu-scre...
- carterschonwald 16y ago
  off hand from just playing with tmux for the past 20 minutes, it looks like tmux better abstracts its commands from how it internally tracks the windows and sessions than does screen. In particular, when i've played with screen, i found that i was frequently stymied by the broken abstraction of the way screen stored its state vs what I wanted to do. byobu sadly doesn't work on macbooks, but it looks cool!
  - carterschonwald 16y ago
    to further clarify: when choosing a session (and thus a collection of windows), in screen the process id info etc is exposed at the user level, which perhaps is useful to someone, but not for how use terminal and such. Thus because these things are not as directly exposed via the interaction model that tmux does, doing stuff becomes simpler and semantically clearer
- petercooper 16y ago
  I did a short (free) screencast about tmux if you want a more visual run-through: http://peterc.org/blog/2010/216-tmux.html http://peterc.org/blog/2010/216-tmux.html
- pyre 16y ago
  tmux was able to split windows vertically before screen was able to mostly due to politics, AFAIK.
carterschonwald 16y ago
thanks! this looks very interesting and worth looking into
grump 16y ago
I'm a fan of dtach + dvtm. tmux looks pretty great too.

adulau 16y ago

A nice function (not mentioned in this presentation) is the ability to send commands (-X) to a specific window in a screen session. This allows you to completely control GNU Screen the shell or another programming environment while benefiting from the persistent or logging of a session. screen -d -m -S mysession screen -S mysession -X screen -a -tjob1 'top' Using -X you can call the commands available within GNU Screen to control the session or the windows.

pyre 16y ago
The Gnu Screen command 'stuff' writes directly to the STDIN on the window. This is how the REPL integration setups with screen/vim that appear on HN from time to time work. e.g. screen -a window1 -X stuff 'import sys' would send 'import sys' to whatever app was reading STDIN on window1.

luu 16y ago

If you haven't heard of it, Xpra is sort of like screen for X, in that it lets you run persistent X sessions (rootlessly, unlike VNC). Shifter (http://shifter.devloop.org.uk/ http://shifter.devloop.org.uk/) packages screen and Xpra together with a nice user-friendly interface for Windows, OpenSolaris, BSD, Mac OS, Linux, etc., and it includes a patch for Xpra so that it works for Windows!

surki 16y ago

I strongly recommend having a look at the Gnu Screen customization in Ubuntu Server. http://blog.dustinkirkland.com/2008/12/ubuntu-server-includes-window-manager.html http://blog.dustinkirkland.com/2008/12/ubuntu-server-include...

mhansen 16y ago
That project has matured a lot, it's now called byobu. It's friggin' awesome. https://launchpad.net/byobu https://launchpad.net/byobu

moe 16y ago

I love screen. I use it on a daily basis for ~10 years. What still bothers me mightily is that, up to this day, nobody has bothered to get the history scrolling right (neither in tmux, btw). You still have to press an awkward key combination to switch to "copy mode", the normal mechanisms (PGUP, mousewheel, scrollbar) only result in garbage. I've tried various partial fixes ("altscreen off") but none works properly across sessions or with multiple windows. Years back I even tried to patch screen myself but had to surrender over the (for me) crufty code-base. And that despite the solution being fairly obvious: Just redraw the entire window while scrolling, just like irssi and plenty other console apps do it. And just like screen itself does it in copy-mode. I wish someone would finally take on this issue...

bricestacey 16y ago
You can scroll through the history of your terminal, but not of individual screens by adding this to your .screenrc file. termcapinfo xterm|xterm-color ti@:te@ Not 100% there, but does well for me.
- moe 16y ago
  Yes I have that, it's the partial solution I mentioned. It unfortunately doesn't preserve the history during detach/reattach. And the history gets scrambled when you switch between windows.

beambot 16y ago

My biggest impediment to using screen is emacs key binding conflicts. I never took the time to determine an acceptable solution. Can an emacs guru share their solution...?

graywh 16y ago
I use ctrl-_ (aka ctrl-7) for screen/tmux commands. I don't its functionality in Vim. Not sure if it helps for Emacs.
Estragon 16y ago
Change the C-a binding to C-z.
nagoff 16y ago
I use backtick as the screen command, which is fine unless you write a lot of bash scripts. $ screen -e '``'
- chrismealy 16y ago
  I'll give that a try ... I had to do screen -e '\`\`'
gojomo 16y ago
So many people hit this, and then use screen less, and everyone adopts a different alternative. I suspect a screen fork which simply adopts new standard emacs/bash-compatible defaults could eventually overtake the original in usage.

Locke 16y ago

I was just thinking today how wonderful it would be if my web browser let me navigate tabs with the same key bindings as screen. If I had a nickel for every time I've done "select all" when I wanted to quickly switch back to the last active tab.