path = "20-01-10-08-39-40kernel.txt"

def readfile(name):                   
    fin=open(name, 'r')
    fout = open(path + ".out.txt", 'w')
    for lines in fin.readlines():         #按行读取text中的内容
        if 'IBAT=' in str(lines): 
            #print(lines)
            index = lines.find('IBAT=')
            index2 = lines.find(': VSYS=')
            fout.write(lines[index + 7: index2] + '\n')
    
    fout.close()
    fin.close()

if __name__ == "__main__":
    readfile(path)