On Sat, May 26, 2012 at 4:07 PM, Chris Jones <cjns1...@gmail.com> wrote:
> On Sat, May 26, 2012 at 06:32:03PM EDT, Britton Kerin wrote:
>
>> I wanted to create a screen socket with a specific name, and
>> later be able to kill that particular window. I create the window like
>> this:
>>
>> screen -S arduino /dev/ttyACM0
>>
>> I expected to be able to kill it like this:
>>
>> screen -p arduino -X kill
>>
>> But this doesn't work, all that happens is I get an inverted text
>> message at the bottom of the window like this:
>>
>> -X: kill: window required
>>
>> After some google I find that this works:
>>
>> screen -S arduino -X kill
>
>> Here is the description of the -S option in the man page:
>>
>> -S sessionname
>>
>> When creating a new session, this option can be
>> used to specify a meaningful name for the session. This name
>> identifies the session for "screen -list" and "screen -r"
>> actions. It substitutes the default [tty.host] suffix.
>
>> Here is the description of the -p option:
>>
>> -p number_or_name
>
>> Preselect a window. This is useful when you
>> want to reattach to a specific window or you want to send
>> a command via the "-X" option to a specific window. As with
>> screens select command, "-" selects the blank window. As
>> a special case for reattach, "=" brings up the windowlist on
>> the blank window.
>
>> So you can see why I want to use -p, not -S. I think its still worth
>> keeping the man page up to date despite google. I don't know how git
>> works for this project or what the true semantics of -S and -p options
>> are or I could do this myself. If anyone wants to tell me what these
>> option descriptions should be I'll try to get them into git.
>
> First you create a session named ‘arduino’ (the -S flag) and then you
> issue a screen command specifying the session name and using the -p and
> -X flags, which the manual indicates are meant for _a specific window_
> within a screen session, not the session.
>
> From the above commands I can see you created a session named arduino.
>
> Since screen would start up by default with one window (window zero) and
> keeping in mind that screen exits when the last window is killed, you
> could try:
>
> | % screen -S arduino -p 0 -X kill
>
> My understanding is that in the manual screen's terminology regarding
> windows and sessions is that you can create one or more ‘sessions’
> (~screen processes as seen by the OS), each one with one or more
> screen ‘windows’ (or panes.. viewports.. etc.)
You seem to be correct. The -S man page documentation still needs a fix
though. It begins "When creating a new session,... " which is very
misleading. I notice that the Screen User's Manual has this:
‘-S sessionname’
Set the name of the new session to sessionname. This option can be used
to specify a meaningful name for the session in place of the default
tty.host suffix. This name identifies the session for the screen -list
and screen -r commands. This option is equivalent to the sessionname
command (see Session Name).
Which is different text but wrong in the same way. The -S option has semantic
significance that has nothing to do with the creation of new sessions.
It applies in that case but also in others.
I just spent some time trying to figure out how to get a list of all the
windows in a session, to be sure and send the commant to the correct one.
But I couldn't figure it out. I'm using the 'screen /serial/port/dev'
form of the screen command, which doesn't seem to support the n argument
that lets you specify the window number explicitly. 'screen -list' says it
lists sessions, and indeed its output doesn't seem to show window numbers.
I think a general cleanup of the description of the options controlling and
specifying sessions and windows would be worthwhile.
Britton
