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man useradd ...-r This flag is used to create a system account. That is, a userwith a UID lower than the value of UID_MIN defined in /etc/login.defsand whose password does not expire. Note that useradd will not create ahome directory for such an user, regardless of the default setting in/etc/login.d 阅读全文
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# The is the ASYN example for communication to 4 simulated motors# "#!" marks lines that can be uncommented.< envPathsdbLoadDatabase("$(TOP)/dbd/motorSim.dbd")motorSim_registerRecordDeviceDriver(pdbbase)dbLoadTemplate("motor.substitutions")# Create simulated motors: 阅读全文
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Soft motor. It is not a simulated motor, it is a way of making a "pseudo-motor", which typically coordinates the motion of several real motors or other devices.simulated motor, which is in the MotorSimSrc directory.That is what you should use for getting familiar with the motor record with 阅读全文
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local area network (LAN) 局域网wide area network (WAN) 广域网 阅读全文
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callocvoid * calloc ( size_t num, size_t size );Allocate space for array in memoryAllocates a block of memory for an array of num elements, each of them size bytes long, and initializes all its bits to zero.The effective result is the allocation of an zero-initialized memory block of (num * size) by 阅读全文
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pathname = /path/to/you/file/filename.txt const char * filename; if ((filename = strrchr (pathname, '/')) == NULL) { filename = pathname;} else { filename++; }filename = filename.txt 阅读全文
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/24表示掩码是 255.255.255.0 /25表示掩码是 255.255.255.128 /17表进掩码是 255.255.128.0 /16表进掩码是 255.255.0.0 阅读全文
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以root用户登陆输入vipw，编辑/etc/passwd文件，修改id值输入vigr，编辑/etc/group文件，修改id值重新登陆，即可看到生效这里需修改文件所有者，因为文件属性是由id值决定的输入chown -R user:user /file 更改相应文件夹所有权为相应的用户和组 阅读全文
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To add a user to the system:Issue the useradd command to create a locked user account:useradd <username>Unlock the account by issuing the passwd command to assign a password and set password aging guidelines:passwd <username> 阅读全文
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查看文件权限的语句： 在终端输入: ls -l xxx.xxx （xxx.xxx是文件名） 那么就会出现相类似的信息，主要都是这些： -rw-rw-r-- 一共有10位数 其中： 最前面那个 - 代表的是类型1. 档案的类型和权限。第一个字符“-”代表 “/root/install.log”这个档案是一个档案文件。常见的档案类型标志请见下边：d 文件夹 - 档案 l 链接档，类似windows的快捷方式 b 随即存取设备，如cd_rom，u盘等等 c 一次性存取设备，如键盘，鼠标等等 s socket，资料接口文件，常用于网络数据承接 p pipe（FIFO）,即先进先出，数据传输... 阅读全文