some common utility functions

comm.sh

function log()
{
    local msg=$1
    now=`date "+%Y-%m-%d %H:%M:%S"`

    i=${#FUNCNAME[@]}
    lineno=${BASH_LINENO[$i-2]}
    file=${BASH_SOURCE[$i-1]}

    echo "${now} ${file}:${lineno} ${msg}"
}

function check_running()
{
    if [ $# -ne 1 ]; then
        log "must specify a pid file"
        exit 1
    fi
    local pidfile=$1

    if [ ! -f $pidfile ]; then
        touch $pidfile
    fi

    ps -p `cat ${pidfile}` > /dev/null
    if [ $? -eq 0 ]; then
        log "already running"
        exit 0
    else
        log "I'm running $$"
        echo $$ > ${pidfile}
    fi
}