n1 = sprintf('%s%04d%s', conf['PORT']['testlogbase']+'bigint_',i-2,'.txt')
n2 = sprintf('%s%04d%s', conf['PORT']['testlogbase']+'bigint_',i-1,'.txt')
File.rename(n1, n2)
n1 = sprintf('%s%04d%s', conf['PORT']['testlogbase']+'bigint_',i-2,'.txt')
n2 = sprintf('%s%04d%s', conf['PORT']['testlogbase']+'bigint_',i-1,'.txt')
File.rename(n1, n2)