Linux 系统日常维护命令
======================

.. versionadded:: @2013-08-22
   创建
.. versionchanged:: @2019-01-25
   增加进程管理

软件包维护
----------

常见发行版（Gentoo，Debian/Ubuntu，RHEL/CentOS）的软件包维护命令。

.. list-table:: 日常维护命令列表
    :header-rows: 1

    * - 功能
      - Gentoo
      - Debian/Ubuntu
      - RHEL/CentOS
    * - 软件包同步
      - * `emerge --sync`
        * `eix-sync`
      - `apt-get update`
      -
    * - 更新所有安装的软件
      - `emerge -auvDN world`
      - * `apt-get upgrade`
        * `apt-get --just-print upgrade` 不实际更新
      - `yum update`
    * - 搜索软件
      - `emerge -s busybox`
      - `apt-cache search busybox`
      - `yum search busybox`
    * - 安装/更新软件
      - `emerge -av busybox`
      - `apt-get install busybox`
      - * `rpm -[i|U]vh \*.rpm`
        * `yum [install|update] busybox`
    * - 删除软件
      - `emerge -C busybox`
      - * `apt-get remove busybox`
        * `apt-get purge busybox`
      - * `rpm -e busybox`
        * `yum remove busybox`
    * - 自动清除不需要的软件
      - `emerge --depclean`
      - `apt-get autoremove`
      - `package-cleanup --leaves`
    * - 查看软件包安装的文件列表
      - * `qlist busybox`
        * `equery files busybox`
      - `dpkg -L busybox`
      - `rpm -ql bash`
    * - 查找文件所属的软件包
      - * qfile /etc/sysctl.conf`
        * `equery belongs /etc/sysctl.conf`
      - `dpkg -S /etc/sysctl.conf`
      - `rpm -qf /etc/sysctl.conf`
    * - 列出所有安装的软件包
      - * `equery list \*`
        * `equery list -i` (gentoolkit <0.3)
      - * `dpkg -l` / `dpkg-query -l`
        * `apt list --installed`
      - `yum list installed`
    * - 校验软件包
      - `equery check busybox`
      - `cd / && md5sum -c /var/lib/dpkg/info/busybox.md5sums`
      - `rpm -V busybox`
    * - 查看安装包版本
      - `equery uses bash`
      - `dpkg-query -W -f='${Version}' bash`
      - `rpm -qi bash`
    * - 查看二进制包内容
      -
      - `dpkg -c \*.deb`
      - `rpm -qpl \*.rpm`
    * - 包证书管理
      -
      - * `apt-key update`
        * `apt-key adv --keyserver keyserver.ubuntu.com --recv {KEYID}`
        * `apt-key add -`
      -
    * - 更新历史日志
      - `/var/log/emerge.log`
      - `/var/log/apt/history.log`
      -

Gentoo 更新步骤
---------------

.. versionadded:: @2018-12-20
   创建

* `eix-sync`
* `emerge -auvDNgk world`
* `eselect news read`
* `perl-cleaner --all -- -gk`
* `python-updater`
* `revdep-rebuild`
* `cd /etc/ssl && rm ...`
* `emerge --depclean -p`

Portage 配置
^^^^^^^^^^^^

* FEATURES

  * collision-protect

    If you are using FEATURES=collision-protect, Portage will reject
    the upgrade. If this is the case, please temporarily switch to
    FEATURES=protect-owned for the upgrade.

  * preserve-libs

    Preserve libraries when the sonames change during upgrade or downgrade.
    Libraries are preserved only if consumers of those libraries are detected.
    Preserved libraries are automatically removed when there are no remaining
    consumers. Run `emerge @preserved-rebuild` in order to rebuild all
    consumers of preserved libraries.


进程管理
--------

.. versionadded:: @2019-02-14
   创建

* 找出仍在使用被删除文件或动态库的进程

  ``lsof | grep -v -E "\\s(/dev/(zero|shm/.*)|/\\[aio\\]|/tmp/\\S* \\(deleted\\))$" | grep -E "( \\(deleted\\)$|\\s+DEL\\s+)\\s?"``


用户/组管理
-----------

.. versionadded:: @2013-08-07
   创建

* 由标准输入修改密码：`echo "root:password" | chpasswd`
* 验证密码是否正确：

  .. code-block:: shell

    SHADOW0=$(awk -v user=root -F: '{if ($1 == user) {print $2;}}' /etc/shadow)
    SALT=$(echo $SHADOW0 | awk -F\$ '{print $3;}')
    SHADOW1=$(echo password | mkpasswd -S "${SALT}" -s -m SHA-512)
    [ ${SHADOW0} = ${SHADOW1} ] && echo "password correct"

* 基于 uid/gid 排序 /etc/passwd， /etc/group 文件：

    * `sort -n -t ':' -k3 /etc/passwd`
    * `pwck -s` / `grpck -s`