shell


Here a very simple init script tested on Suse SLES 10. An other good way to create one is looking at the init-Script for tomcat or using just it and installing Jira as WAR into tomcat.

#!/bin/bash
# Jira startup script
# install:
# copy to /etc/init.d/jirad
# ln -s /etc/init.d/jirad /sbin/rcmy-jirad
# insserv /etc/init.d/jirad
 
### BEGIN INIT INFO
# Provides:          jirad
# Required-Start:    $local_fs $network
# Required-Stop:
# Default-Start:     3 5
# Default-Stop:      0 1 2 6
# Short-Description: Starts Jira server
# Description:       Starts Jira Issue Tracking
### END INIT INFO
# Based on script at  http://confluence.atlassian.com/pages/viewpage.action?pageId=183148
 
RUN_AS_USER=jico
CATALINA_HOME=/opt/jira
 
start() {
        echo "Starting Jira: "
        if [ "x$USER" != "x$RUN_AS_USER" ]; then
          su - $RUN_AS_USER -c "$CATALINA_HOME/bin/startup.sh"
        else
          $CATALINA_HOME/bin/startup.sh
        fi
        echo "done."
}
stop() {
        echo "Shutting down Confluence: "
        if [ "x$USER" != "x$RUN_AS_USER" ]; then
          su - $RUN_AS_USER -c "$CATALINA_HOME/bin/shutdown.sh"
        else
          $CATALINA_HOME/bin/shutdown.sh
        fi
        echo "done."
}
 
case "$1" in
  start)
        start
        ;;
  stop)
        stop
        ;;
  restart)
        stop
        sleep 10
        #echo "Hard killing any remaining threads.."
        #kill -9 `cat $CATALINA_HOME/work/catalina.pid`
        start
        ;;
  *)
        echo "Usage: $0 {start|stop|restart}"
esac
 
exit 0

Here is an init script to control hudson start up at boot time. It is tested on SLES 10 . I am not commenting it in detail here, nevertheless you are welcome to ask and leave comments. It’s rather beta but I hope that it could be useful as a starting point.

#!/bin/bash
# Author: Konstantin.rekk@gbv.de, 2008
# Using ideas from http://developer.novell.com/wiki/index.php/Writing_Init_Scripts
#
# install:
# copy to /etc/init.d/gbv-hudson-integration
# ln -s /etc/init.d/gbv-hudson-integration /sbin/rcgbv-hudson-integration
# insserv /etc/init.d/gbv-hudson-integration
 
 
### BEGIN INIT INFO
# Provides:          gbv-hudson-integration
# Required-Start:    $local_fs $network
# Required-Stop:
# Default-Start:     3 5
# Default-Stop:      0 1 2 6
# Short-Description: Starts the hudson server for CI 
# Description:       Starts Continuous Integration System for VZG SOA
### END INIT INFO
 
# to avoid conflict with functions local $1
ARG=$1
 
APP="hudson"
 
HUDSON_USER=soarun
HUDSON_GROUP=soarun
export HOME=/home/${HUDSON_USER}
export VZGSOA_HOME=${HOME}/soa-workarea
 
# include rc.status functions 
test -s /etc/rc.status && . /etc/rc.status && rc_reset
 
# use test_for_app <appl|file> (x|f)
test_for_app ()
{
    app_found=0
    if [ "f" = "$2" ] && [ -f $1 ]; then
        app_found=1
    elif [ "x" = "$2" ] && [ -x $1 ]; then
        app_found=1
    fi
    if [ 0 = $app_found ]; then
        echo -n "Warning:  Couldn't find $1"
        if [ "$ARG" = "stop" ] ; then
            rc_failed 0
        else
            rc_failed 5
        fi
        rc_status -v
        rc_exit
    fi
}
 
test_for_app $VZGSOA_HOME/vzgsoa.env f
test_for_app $VZGSOA_HOME/integration/integration.env f
. $VZGSOA_HOME/vzgsoa.env
. $VZGSOA_HOME/integration/integration.env
 
HUDSON_CMD="${JAVA} -jar ${HUDSON_WAR} --httpPort=${CI_HTTP_PORT} --argumentsRealm.passwd.hudson=${HUDSON_PW} --argumentsRealm.roles.hudson=admin"
 
HUDSON_PIDFILE=/var/run/hudson.pid
HUDSON_LOG=/var/log/hudson
 
usage ()
{
    echo ""
    echo "Usage: $0 <command> "
    echo ""
    echo "where <command> is one of the following:"
    echo "    start - start $APP if not running"
    echo "    stop - stop $APP if running"
    echo "    status - report whether $APP is running"
    echo "    restart - stop and restart $APP"
    echo "    usage, help - print this message"
}
 
get_pid_for_cmd ()
{
    for pid in `ls /proc`; do
        if [ -d /proc/$pid ] && [ -f /proc/$pid/cmdline ]; then
            if [ "$1" = "$(</proc/$pid/cmdline)" ]; then
		# return with current pid 
                return
            fi
        fi
    done
    pid=0
}
 
# checkport <port>
# returns port_used
check_port()
{
	port=$1
	if netstat -nlept 2>/dev/null | grep --regexp=":$port " &>/dev/null ; then
        	port_used=1
    	else
        	port_used=0
    	fi
}
 
# checks hudson, sets/returns status - 
# 0 if pidfile same as pid, running
# 3 no pidfile, not running (what with running?)
# 2 pidfile, but no process (remove file ...), not running
# 1 pidfile != pid, but running
# 4 no pidfile, but running
# 
# @todo: check port usage
check_hudson() 
{
	get_pid_for_cmd `eval echo ${HUDSON_CMD} | sed -e 's/ //g'`
 
	if [ -f $HUDSON_PIDFILE ]; then
		pidfile_pid=`cat $HUDSON_PIDFILE`
		if [ 0 = $pid ]; then
			status=2
		elif [ "$pid" = "$pidfile_pid" ]; then
			status=0;
		else 
			status=1;
		fi		
	else 
		if [ 0 = $pid ]; then
			status=3;
		else 
			status=4;
		fi
	fi
 
}
 
 
test_for_app ${JAVA} x
test_for_app ${HUDSON_WAR} f
 
case "$1" in
    start)
        check_hudson
        case "$status" in
            0)
                echo "${APP} already running"
		rc_failed 0
		rc_status -v1
           	rc_exit
                ;;
	    1|4)
		echo "${APP} seems running but pidfile is not up to date or doesn't exist, please check!"
		rc_failed
                rc_status -v1
                rc_exit
		;;
            2)
                echo "Found stale pidfile for ${APP} - unclean shutdown?"
                rm ${HUDSON_PIDFILE}
                ;;
            3)
                # not running - ok
        	check_port $CI_HTTP_PORT
		if [ $port_used = 1 ]; then
			echo "Port $CI_HTTP_PORT already in use, pleas check!"
                	rc_failed
                	rc_status -v1
                	rc_exit
		fi 
                ;;
            *)
                echo "Check for ${APP} failed"
                rc_failed
                rc_status -v1
                rc_exit
        esac
 
        echo -n "Starting ${APP}"
        startproc -f -u $HUDSON_USER -g $HUDSON_GROUP -p ${HUDSON_PIDFILE} ${HUDSON_CMD} >> ${HUDSON_LOG} 2>&1
        if ! [ 0 = $? ]; then
            echo -n "(Error - "
            case $? in
                2)
                    echo -n "invalid arguments"
                    ;;
                4)
                    echo -n "insufficient permission"
                    ;;
                5)
                    echo -n "no such program"
                    ;;
                7)
                    echo -n "launch failure"
                    ;;
                *)
                    echo -n "unspecified error"
                    ;;
            esac
            echo -n ")"
            rc_failed
            rc_status -v1
            rc_exit
        fi
	# removing spaces from commandline to be able to compare with /proc/<pid>/cmdline
        get_pid_for_cmd `eval echo ${HUDSON_CMD} | sed -e 's/ //g'`
        if [ 0 = $pid ]; then
            echo "Warning - Couldn't obtain PID for ${APP} "
        else
            echo $pid > ${HUDSON_PIDFILE}
        fi
        rc_status -v
        ;;
    stop)
        if [ $1 = "stop" ]; then
            check_hudson
	    if ! [ $status = 0 ]; then
		echo "Warning - not running!"
	    fi
            killproc -p ${HUDSON_PIDFILE} -t 10 ${JAVA}
            rc_status -v
        fi
        ;;
    status)
        check_hudson
	case "$status" in
        0)
            echo -n "(running)"
            rc_failed 0
            ;;
	1|4)  
	    echo -n "(running)"
	    echo -n  "Warning - PID corrupted"
            rc_failed 0
            ;;
        2)
            echo "(not running)"
            echo -n "Warning - PID file found"
            rc_failed 3
            ;;
        3)
            echo -n "(not running)"
            rc_failed 1
            ;;
        *)
            echo "(unknown)"
            echo "Warning - Couldn't get status"
            rc_failed 1
            rc_status -v1
            rc_exit
    esac
    rc_status -v
        ;;
    restart)
        $0 stop &>/dev/null
        $0 start &>/dev/null
        rc_status -v
        ;;
    usage|help)
        usage
        rc_exit
        ;;
    *)
        usage
        rc_failed 1
        rc_status -v
        rc_exit
esac

Have you ever been surprised by obvious, even trivial facts which you have been overlooking for years?

Today it hit me:
I used shell metacharacters for expansion and even wrote quite complex bash scripts and used tree (not installed by default in ubuntu) to look into a given display depth of the directory tree. But a combination of ls and shell expansion can do quite the same:

ls */*
ls */*/*

Another interesting example from the same category is
echo */
to list all directories in working directory.

One more example – List only the directories :
ls -d */
works similiar to
find . -type d -maxdepth 1 -mindepth 1

Say you want to record a video live stream from the internet for example from the Streaming CCC Congress in Berlin 2007.

This can be accomplished using the glorious mplayer HOWTO Rip Streams With MPlayer.

To stop the recording after a certain amount of time use this simple script (see also my post Finding Child Process Pids … ):

#!/bin/bash
URL=$1
FILE=$2
# duration in minutes
DURATION=$3
mplayer -framedrop -autosync 30 -cache 10000 -dumpstream $URL -dumpfile $FILE &amp;amp;
sleep $DURATIONm
kill %+

Now you need to start this script at a certain time. For that you could use the linux “at” command (see at). To run it you have to export the DISPLAY variable on ubuntu (see Bug #94933):
export DISPLAY=$DISPLAY ; export TERM=$TERM; echo "echo 'Hallo'" | at  now

But I prefer KAlarm from KDE to schedule tasks which should run only once.
Run KAlarm, create New Alarm, choose Action “Command”, enter the path to your script with appropriate arguments for stream url, dumpfile and duration in minutes:
/home/myhome/scripts/stream_ripper.sh mms://streaming-internet.fem.tu-ilmenau.de/saal3 test.asf 60
, adjust all other settings which are quite self explaining. Use the template feature of KAlarm for similiar tasks.

To control background child processes from a shell script you want to know the PID or job-id of the child. Here are some ways to do this:

First starting a background process echoes the job-id and pid of the process:

$ emacs &amp;
[1] 15393

The PID of the last command set to run in the background by the current shell or script is stored in $! variable:
$ echo $!
15393

This you could find out by using the jobs command:
$ PID=`jobs -l | sed -n 's/^\[[0-9]*\] *+  *\([0-9]*\) .*$/\1/p'`; echo $PID
using the fact that the last current (last started) job will be marked by a + in
jobs -l output.
To terminate the current job you don’t need the explicit job-id:
$ kill %+
The exit status will be stored in the $? variable.
Read more in the Advanced Bash-Scripting Guide:Job Control Commands

I already wrote how to configure the ssh-client for single-sign-on in Convenient SSH on Linux. Today I would like to jump up to the KDE-Layer and see what there can be done to organize networking more effectively. Formerly I used kssh to organize my ssh-accounts (see Installing kssh on ubuntu). Nowadays I prefer a combination of KDE’s Network Folders and Terminal Sessions.

KDE Network Folders can help you to organize your remote access links. It is based on KDE’s support of webdav, ftp, sftp, smb and fish. Fish is quite interesting, it presents files over ssh just as they would be local. There is a special directory where your network folders are stored – type "remote:/" into Konqueror’s address bar. (Other possibility is of course to use simple bookmarks to organize remote connections accessed via “sftp://user@host/” or similiar.) It is just a collection of links which are stored in .kde/share/apps/remoteview by KDE.
The real value of Network Folders lies in the combination with Network Folder Wizard which gives you a configuration interface and quick access list in KDE’s panel.
Read the documentation of knetattach in Konqueror "help:/knetattach/introduction.html" which is the application behind Network Folders administration, also known as Network Folder Wizard also available as an applet by "RightClick Panel" -&gt;  "Add Applet to Panel" -&gt; "Network Folders".

Teminal Sessions is an other applet you can add to your panel. It will list the different konsole sessions. I use sessions to configure ssh shell access and to execute common shell commands like watching remote logs etc. . To add a session open a konsole window, in the menubar click "Settings" -&gt; "Configure Konsole" -&gt; "Session"-tab . In the “General” group type a name for your session, the command to execute (example: ssh xxx.gebewau.de) and your working directory, click save session. You can associate different color schema and icons with different sessions to have better orientation between konsole windows for different purposes. There seems to be no grouping feature for session links.

Was looking around to find a simple method to find the fullpath or explicit path for the script running.
After a while of searching I found this useful simple snippet: bash, full filename.
And used it like this in the beginning of the script:

PRG="$0"
OLDPWD=`pwd`
B=`basename $PRG`
P=`dirname $PRG`
#  echo BASE:$B  PATH:$P
cd $P
if [ `pwd` != "/" ]
then
FULLNAME=`pwd`/$B
else
FULLNAME=/$B
fi
echo $FULLNAME
cd $OLDPWD
echo `pwd`

… simple but effectiv.

In linux you can use some shell scripting to find a running server process by port number. I came up with this example using awk (watch out for backticks `):

ps aux | grep --regexp="`netstat -nlept | awk '/:8079 / || /:8080 / {split($9,t,"/"); print t[1]}'`"

where you suspect the server ports to be 8079 or 8080. Problem here – if nothing is found then all processes will be listed. For automation you might prefer:

ps u --no-heading -p  `netstat -nlept | awk '/[:]8080 / {split($9,t,"/"); print t[1]}'` 2>/dev/null

… last part will redirect error/help message in case there is no process.

Or put it into a function:

myserver_info() { ps aux | grep --regexp="`netstat -nlept | awk '/8079/ || /8080/ {split($9,t,"/"); print t[1]}'`"; }

this definition you can add to your .bashrc .

Usage:

myserver_info

or pass it within a pipe to “kill <pid>” command for example.

You can extend it further by passing the ports as function arguments … (see Advanced Bash-Scripting Guide: Functions)

Do you know a shorter way to do the same?