Screen -X exec commands not working until manually attached
- by James Watt
I have a batch script that starts a java server application inside of a screen. The command looks like this:
cd /dir/ && screen -A -m -d -S javascreen java -Xms640M -Xmx1024M -jar javaserverapp.jar nogui
After I run the batch script, it starts the server and puts it inside the correct screen. If I list my screens after, I see something like this:
user@gtwy /dir $ screen -list
There is a screen on:
16180.javascreen (Detached)
1 Socket in /var/run/screen/S-user.
However, I have a second batch script that sends automated commands to this server and runs on a different crontab interval. Because of the way the application works, I send commands to it like this (this command tells it to alert connected users "testing 123"):
screen -X exec .\!\! echo say testing 123
I've also tried:
screen -R -X exec .\!\! echo say testing 123
screen -S javascreen -X exec .\!\! echo say testing 123
Unfortunately, these commands DO NOT WORK. They don't even give me an error message, they just do nothing.
HOWEVER - If I manually attach to the screen first (with the below command) and then detach, now I can run any of the above commands flawlessly. I can demonstrate this with a video, if I wasn't clear enough here.
screen -r -d
Thanks in advance.
Update: here is the important parts of /etc/screenrc. It should be totally vanilla, I've never edited this file.
# VARIABLES
# ===============================================================
# No annoying audible bell, using "visual bell"
# vbell on # default: off
# vbell_msg " -- Bell,Bell!! -- " # default: "Wuff,Wuff!!"
# Automatically detach on hangup.
autodetach on # default: on
# Don't display the copyright page
startup_message off # default: on
# Uses nethack-style messages
# nethack on # default: off
# Affects the copying of text regions
crlf off # default: off
# Enable/disable multiuser mode. Standard screen operation is singleuser.
# In multiuser mode the commands acladd, aclchg, aclgrp and acldel can be used
# to enable (and disable) other user accessing this screen session.
# Requires suid-root.
multiuser off
# Change default scrollback value for new windows
defscrollback 1000 # default: 100
# Define the time that all windows monitored for silence should
# wait before displaying a message. Default 30 seconds.
silencewait 15 # default: 30
# bufferfile: The file to use for commands
# "readbuf" ('<') and "writebuf" ('>'):
bufferfile $HOME/.screen_exchange
#
# hardcopydir: The directory which contains all hardcopies.
# hardcopydir ~/.hardcopy
# hardcopydir ~/.screen
#
# shell: Default process started in screen's windows.
# Makes it possible to use a different shell inside screen
# than is set as the default login shell.
# If begins with a '-' character, the shell will be started as a login shell.
# shell zsh
# shell bash
# shell ksh
shell -$SHELL
# shellaka '> |tcsh'
# shelltitle '$ |bash'
# emulate .logout message
pow_detach_msg "Screen session of \$LOGNAME \$:cr:\$:nl:ended."
# caption always " %w --- %c:%s"
# caption always "%3n %t%? @%u%?%? [%h]%?%=%c"
# advertise hardstatus support to $TERMCAP
# termcapinfo * '' 'hs:ts=\E_:fs=\E\\:ds=\E_\E\\'
# set every new windows hardstatus line to somenthing descriptive
# defhstatus "screen: ^En (^Et)"
# don't kill window after the process died
# zombie "^["
