rotating log file with bash script

logrotate.bash

#!/bin/bash

# rotate log files with bash script.
function _logrotate {
  file=$1
  MAXLOG=10
  
  # return if $file does not exists
  [ ! -f $file ] && return 0
  
  # process file rotation
  for i in `seq $((MAXLOG-1)) -1 1`; do
    [ -f "${file}.${i}" ] && mv -fv "${file}."{$i,$((i+1))}
  done
  mv $file $file.1 
  return 0
}

# sample usage for demo
file=log/test.log
_logrotate $file
date >> $file