# 17.4.2 键命令 * 查找键 参数⽀持正则表达式 ``` keys pattern ``` * 判断键是否存在， 如果存在返回1，不存在返回0 ``` exists key ``` * 查看键对应的value的类型 ``` type key ``` * 删除键 ``` del key1 key2 ... ``` * 设置过期时间 以秒为单位，如果没有指定过期时间则⼀直存在，直到使⽤DEL移除 ``` expire key seconds ``` * 查看有效时间 以秒为单位 ``` ttl key ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://wiki.clay-wangzhi.com/17-redis/17.4-shu-ju-ku-cao-zuo/17.4.2-jian-ming-ling.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.