I use the appender like

<appender name="ROLL-INFO" class="ch.qos.logback.core.rolling.RollingFileAppender">
    <rollingPolicy class="ch.qos.logback.core.rolling.SizeAndTimeBasedRollingPolicy">
      <fileNamePattern>${IR}/vcs-info-%d{yyyy-MM-dd}.%i.log</fileNamePattern>
      <maxFileSize>15MB</maxFileSize>
      <maxHistory>100</maxHistory>
    </rollingPolicy>
    <encoder>
      <pattern>${log-format}</pattern>
    </encoder>
  </appender>

the pattern I specify includes file counter in each day. In may case it may easily turn out I have hundreds of files per day.

The problem is that %i syntax does not allow me to have leading zeroes in the names I generates. This ends up it's a but tricky to look through files list I have on my disk, which are sorted in sexicographical order.

Having an ability to force adding leading zeroes to the pattern will solve the issue.