• CentOS 中 yum update 与 yum upgrade 的区别

    10-12-23 12:31 24383 0 技术

    在 CentOS 系统中,yum upgradeyum update 都会将系统包更新到最新版本。

    通过 man yum 查询到的帮助信息如下:

    update

    If  run  without any packages, update will update every currently installed package.  If one or more packages or package globs are specified, Yum will only update the listed packages.  While updating packages, yum will ensure
    that all dependencies are satisfied. (See Specifying package names for more information) If the packages or globs specified match to packages which are not currently installed then update will not install them.  update  oper-
    ates on groups, files, provides and filelists just like the "install" command.
    
    If the main obsoletes configure option is true (default) or the --obsoletes flag is present yum will include package obsoletes in its calculations - this makes it better for distro-version changes, for example: upgrading from
    somelinux 8.0 to somelinux 9.
    
    Note that "update" works on installed packages first, and only if there are no matches does it look for available packages. The difference is most noticeable when you do "update foo-1-2" which will act exactly as "update foo"
    if foo-1-2 is installed. You can use the "update-to" if you’d prefer that nothing happen in the above case.
    

    upgrade

    Is the same as the update command with the --obsoletes flag set. See update for more details.
    

    唯一不同是:yum upgrade 会删除旧版本的 package,而 yum update 则会保留。注意!如果你的某些软件依赖旧版本的 package,请使用 yum update

  • HTTP状态码 : HTTP Status Code

    10-12-03 11:12 24460 0 技术

    常见的状态码:

    HTTP: Status 200 – 服务器成功返回网页 HTTP: Status 404 – 请求的网页不存在 HTTP: Status 503 – 服务不可用