Mikrotik оставить только последние N

#!/bin/bash

# ....

log "Generate filename..."
bfile=backup-mikrotik-`date +%Y-%m-%d_%H%M%S-$server`
log "name used: $bfile"

log "Create config export files $bfile..."
ssh $server "export file=$bfile"
log "!"

log "Create full system backup files $bfile..."
ssh $server "/system backup save name=$bfile"
log "!"

# Оставляем только последние count=N name=backup-mikrotik* type=backup
log "remove tail backup (type=backup)..."
ssh $server # ??????????????????????

# Оставляем только последние count=N name=backup-mikrotik* type=script
log "remove tail backup (type=script)..."
ssh $server # ??????????????????????