Linux用户管理 0.10 用户资源限制ulimit

> 限制用户使用的系统资源

命令：ulimit
-a 　    显示目前资源限制的设定。
-H       硬性限制，无法超过，只有root能改
-S       软限制，用户可以自己改
-c int 　创建core文件的最大值
-d int 　进程数据段最大值。
-f int 　shell所能建立的最大文件
-m int 　可使用内存的上限
-n int 　同一时间最多可开启的文件数
-p int 　管道缓冲区的大小
-s int 　stack的上限
-t int   CPU使用时间的上限
-u int 　用户最多可开启的进程数
-v int 　可使用的虚拟内存的上限

**永久修改配置**
cat /etc/security/limits.conf 
```
# /etc/security/limits.conf
#
#Each line describes a limit for a user in the form:
#
#<domain>        <type>  <item>  <value>
#
#Where:
#<domain> can be:
#        - a user name
#        - a group name, with @group syntax
#        - the wildcard *, for default entry
#        - the wildcard %, can be also used with %group syntax,
#                 for maxlogin limit
#
#<type> can have the two values:
#        - "soft" for enforcing the soft limits
#        - "hard" for enforcing hard limits
#
#<item> can be one of the following:
#        - core - limits the core file size (KB)
#        - data - max data size (KB)
#        - fsize - maximum filesize (KB)
#        - memlock - max locked-in-memory address space (KB)
#        - nofile - max number of open file descriptors
#        - rss - max resident set size (KB)
#        - stack - max stack size (KB)
#        - cpu - max CPU time (MIN)
#        - nproc - max number of processes
#        - as - address space limit (KB)
#        - maxlogins - max number of logins for this user
#        - maxsyslogins - max number of logins on the system
#        - priority - the priority to run user process with
#        - locks - max number of file locks the user can hold
#        - sigpending - max number of pending signals
#        - msgqueue - max memory used by POSIX message queues (bytes)
#        - nice - max nice priority allowed to raise to values: [-20, 19]
#        - rtprio - max realtime priority
#
#<domain>      <type>  <item>         <value>
#

#*               soft    core            0
#*               hard    rss             10000
#@student        hard    nproc           20
#@faculty        soft    nproc           20
#@faculty        hard    nproc           50
#ftp             hard    nproc           0
#@student        -       maxlogins       unlimited

# End of file

```

乱读天书， 不求甚解

乱读天书，不求甚解