Is it possible to persist the “state” of a GNU screen window (or just a standard shell) so that I can reload everything after a reboot:
- The number of opened shells
- The name of each shell
- The current directory of each shell
- The history of each shell
- If possible, their environment variables
Answers:
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Method 1
It is not really possible to save a complete screen session.
What you can do is to create a proper .screenrc which will setup some things after you restarted your system.
Here are some comments to the things you listed:
- The number of opened shells
- The name of each shell
- The current directory of each shell
I use something like this in my .screenrc to open some specific shells on startup:
## set the default shell shell zsh # screens screen -t 'zsh' screen -t 'mutt' mutt screen -t 'zsh' /home/user/bin/scriptToRun [..]
You will get the string between ” as your window name and the command after the name will be executed on your default shell. Include any script you want, for example change in a specific directory and open some logs.
- The history of each shell
Have you ever thought about sharing the history of the shells across your sessions? IMHO this makes things much more easier. In ZSH its done with setopt SHARE_HISTORY in your .zshrc
- If possible, their environment variables
If you really need this and don’t want any trade-off you could think about a shell script, which reads out the current state of screen, saves the number of shells, environment variables, etc. and puts this information in a startup script called by your .screenrc.
For me this would not be worth the effort because I appreciate a clean environment after a reboot, if I can customize the default windows for screen.
Method 2
I’ve stumbled upon a project called screen-session. It allows you to save and reload GNU Screen sessions to some extent.
Method 3
There is a tool to freeze the state of a process called cryopid. However, currently it doesn’t work with GNU screen as it doesn’t support re-creating a hierarchy of sub-processes. They state that they want to achieve this in the future but the project doesn’t seem to be too active at the moment. Nevertheless, you might want to trace their progress.
Method 4
I built a similar thing on solaris years back. Not even screen-related; it was session related. “if $TTY = whatever”. echox has the right idea.
tip: if you’re doing this across multiple machines, recognize that each machine deserves its own definition of what should be done when you login there, rather than all being the same per your nfs mounted /home or similar.
HTH,
-pbr
Method 5
A script to automate the “saving” of screen sessions can be found here https://github.com/simonwalz/screen-save
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