logrotate.sh

#!/bin/bash

function logrotate {
    FNAME=$1
    MAX=$2
    for IDX in `seq ${MAX} -1 1`
    do
        OLD=$(( $IDX - 1 ))
        if [ -e "${FNAME}.${OLD}" ]
        then
            mv "${FNAME}.${OLD}" "${FNAME}.${IDX}"
        fi
    done
    if [ -e "${FNAME}" ]
    then
        mv "${FNAME}" "${FNAME}.1"
        touch "${FNAME}"
    fi
}

cd /var/log
logrotate something.log 10