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How to create custom startup scripts
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How to create custom startup scripts

Contents

Template "/sbin/rc3.d/S999custom1"

#!/sbin/sh
#
# Template for custom rc script
PATH=/usr/sbin:/usr/bin:/sbin
export PATH

case $1 in
'start_msg')
        echo "Starting the <script>"
        ;;

'stop_msg')
        echo "Stopping the <script>"
        ;;

'start')
        # All required instruction to start the process. Can be a call to another script.
        rval=1
        ;;

'stop')
        # All required instruction to stop the process. Can be a call to another script.
        rval=1
        ;;

*)
        echo "usage: $0 {start|stop|start_msg|stop_msg}"
        rval=1
        ;;
esac

exit $rval

Example using a pseudo daemon process

The following example demonstrates a basic startup script using a Posix Shell while loop. The script uses the su command to start the script under bin user profile. Note that to properly stop the process, the process ID of the su child process is used. This is due to the nested nature of calling a shell under a shell approach and not needed when calling binary executables or scripts that don't need to change the user.

1. Create "pseudo.sh" daemon.

# cat > /tmp/pseudo.sh << EOF
#!/bin/sh
# Pseudo daemon

while true
do
echo $(date) >> /tmp/test.txt
sleep 60
done
EOF
# chown bin:bin /tmp/pseudo.sh
# chmod 0744 /tmp/pseudo.sh


2. Test that pseudo daemon works from the command line.

# su bin -c '/tmp/pseudo.sh' &
[1]     16158

# ps -ef | grep [p]seudo.sh | awk '{print $2}' | sort -nr | head -n 1 > /tmp/pseudo.pid

# ps -ef | grep [p]seudo.sh
     bin 16160 16158  0 11:55:24 pts/tg    0:00 /bin/sh /tmp/pseudo.sh
     bin 16158 15944  0 11:55:24 pts/tg    0:00 sh -c /tmp/pseudo.sh

# cat /tmp/pseudo.pid

# kill -9 $(cat /tmp/pseudo.pid)
# sh: 16160 Killed

# ps -ef | grep [p]seudo.sh


3. Implement the previous login using the RC startup script.

# cat /sbin/init.d/pseudo

#!/sbin/sh
#
# Pseudo daemon Startup Script
PATH=/usr/sbin:/usr/bin:/sbin
export PATH
 
case $1 in
'start_msg')
        echo "Starting the pseudo daemon process"
        ;;
 
'stop_msg')
        echo "Stopping the pseudo daemon process"
        ;;
 
'start')
        # All required instruction to start the process. Can be a call to another script.
        username="bin"
        su ${username} -c '/tmp/pseudo.sh' &
        sleep 1
        ps -ef | grep [p]seudo.sh | awk '{print $2}' | sort -nr | head -n 1 > /tmp/pseudo.pid
        rval=1
        ;;
 
'stop')
        # All required instruction to stop the process. Can be a call to another script.
        if [[ -f /tmp/pseudo.pid ]]; then
           kill -9 $(cat /tmp/pseudo.pid)
           if [[ $? -eq 0 ]]; then
              rval=1
           else
              rval=0
           fi
        fi
        rval=1
        ;;
 
*)
        echo "usage: $0 {start|stop|start_msg|stop_msg}"
        rval=1
        ;;
esac
 
exit $rval
# chown bin:bin /sbin/init.d/pseudo
# chmod 0755 /sbin/init.d/pseudo


4. Test the start and stop routines

# /sbin/init.d/pseudo
usage: /sbin/init.d/pseudo {start|stop|start_msg|stop_msg}

# /sbin/init.d/pseudo start

# ps -ef | grep [p]seudo
     bin 16332 16325  0 12:09:33 pts/tg    0:00 /bin/sh /tmp/pseudo.sh
     bin 16325     1  0 12:09:33 pts/tg    0:00 sh -c /tmp/pseudo.sh

# /sbin/init.d/pseudo stop

# ps -ef | grep [p]seudo

Reference

Authors

This page was last modified on 20 April 2011, at 16:57. This page has been accessed 1,668 times.