linux删除增加指定文件内容

    def delLastText(self, fileName):
        """
        删除指定文件最后一行
        """
        self.cmd('cd /var/www/html/http/')
        self.cmd('pwd')
        self.cmd("sed -i '$d' %s" % fileName)
        result = self.cmd('cat %s' % fileName)
        return result

    def addLastText(self, fileName, text):
        """
        给某个文件添加内容
        """
        self.cmd('cd /var/www/html/http/')
        self.cmd('pwd')
        self.cmd("echo '%s' >> %s" % (text, fileName))
        result = self.cmd('cat %s' % fileName)
        return result