Shell Programming and Scripting

#!/bin/sh
# chkscr: checks if the server is running.

CBPATH=/home/*user*/*serverdir*
SESSION="server1"
DAEMON="screen -d -m -S $SESSION /home/*user*/*serverdir*/exec"

if test -r $CBPATH/cb.pid; then
    CBPID=$(cat $CBPATH/cb.pid)
    if $(kill -CHLD $CBPID >/dev/null 2>&1)
    then
	exit 0
    fi
fi

echo "Restarting Server"
$DAEMON & echo $! > cb.pid

#!/bin/bash

while true; do
java *server variables*
wait
done

echo $$ >$CBPATH/cb.pid

#!/bin/sh
# chkscreen: checks if a screen session is running.
WORKINGDIR=/home/mute/test
PIDFILE=cb.pid
SESSION="server1"
DAEMON="/home/mute/test/java-daemon.sh"

is_running()
{
    pid=$1
    name=$2
    [ -z "$pid" ] && return 1
    [ ! -d /proc/$pid ] &&  return 1
    cmd=`cat /proc/$pid/cmdline | tr "\000" "\n"|tail -n 1 |cut -d : -f 1`
    [ "$cmd" != "$name" ] &&  return 1
    return 0
}

# does the session exist?
#screen -S $SESSION -ls -q 2>&1 >/dev/null

# check java-daemon.sh's pid instead?
pid=$(cat $PIDFILE 2>/dev/null)
is_running "$pid" "$DAEMON"

if [ $? != 0 ]; then
        echo "Restarting $DAEMON"
        screen -d -m -S $SESSION $DAEMON
fi

#!/bin/sh
# java-daemon.sh: keeps restarting a buggy server... ;)

WORKINGDIR=/home/mute/test
PIDFILE=cb.pid

cd $WORKINGDIR
echo $$ >$PIDFILE

while true; do
top
done

# check java-daemon.sh's pid instead?
pid=$(cat $PIDFILE 2>/dev/null)
kill -0 $pid 2>/dev/null

if [ "$?" != 0 ]; then
        echo "Restarting $DAEMON"
        screen -d -m -S $SESSION $DAEMON
fi

#!/bin/bash
# chkscr: Checks if server is running, if not, restarts it

# screen name
SESSION="server1"

# screen session and exec script
DAEMON="screen -d -m -S $SESSION /home/user/serverdir/exec"

# Gets exec's PID
PROPID=$(ps -aef | grep -v grep | grep '/bin/bash /home/user/serverdir/exec' | awk '{print $2}')

# Get PID value from file
read val < cb.pid

# Checks if exec's PID and file PID are same, sends message, then exits
if [ "$PROPID" -eq "$val" ]; then
screen -S $SESSION -X exec .! echo 'message Test complete.'
exit 0
fi

# If above check fails, deletes PID file
rm cb.pid

# Sends message, restarts server, remakes PID file with exec's PID for above check
echo "Restarting the server now."
$DAEMON
ps -aef | grep -v grep | grep '/bin/bash /home/user/serverdir/exec' | awk '{print $2}' > cb.pid

#!/bin/bash
# exec: Starts the server from inside the screen and restarts it, if stopped

while true; do
java server variables
wait
done