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eXerCISe 1-1: WOrKING WIth LINUX COMMaNDS 1. Log in to your Linux machine as root and open a shell. 2. type useradd lisa to create a user with the name lisa. 3. type passwd lisa. this command will prompt you for the password that you want to use. enter the password “password” and when asked for confirmation, enter it again. notice that this command will give you a warning about the password being too simple, which you can safely ignore. 4. use Ctrl-D to close the shell you are currently logged in to. if it was a nongraphical shell, you’ll now see a login prompt. if you’re working from a graphical environment, find the option that logs you out of your current session. 5. Log in again, this time as user lisa and open a shell. 6. type ls -l iwehig. this should give you an error message. 7. type ls il iwehig 2> ~/errors. this command redirects all errors to a file with the name errors that is created in your home directory. 8. type cat ~/errors to view the contents of this file. 9. type ls --help to view a list of options that can be used with the ls command. You’ll notice that the list is too long and doesn’t fit on the screen. 10. type ls --help | less to pipe the output of the ls command to less. You can now use the arrow keys to move up and down in the output. 11. press q to quit the less viewer. eXerCISe 1-2: GettING heLp 1. type man 3 intro. every section in the man pages has an intro page, describing the purpose of the section. 2. type man lvcreate. use /examples to look for the word examples. many man pages have an examples section near the end of the man page. in this section you can often find useful usage information. 3. type man -k sander. it will tell you “nothing appropriate”. if this happens on commands that you do expect to be available on your computer, it’s a good idea to use mandb to generate the new man pages index file. eXerCISe 1-3: WOrKING WIth the SheLL 1. Log in as root. 2. type echo LANG. this echoes the text Lang to the Stdout. 3. type echo $LANG. this echoes the current contents of the language variable to the Stdout. 4. type.UTF-8. You have now set the language variable to the French language. 5. type ls --help. You’ll notice that the output of the command shows in French. notice that on some distributions the language packages are not installed by default, so you won’t see a change in language after doing this. 6. Create a user florence, using the command useradd -m florence. use passwd florence to set the password for user florence. Set it to “password” 7. Log in as user florence and type echo.UTF-8 >> ~/.bashrc. this appends the Lang variable with its new value to the .bashrc file in this users home directory. 8. Still as florence, type ls --help. You’ll see the output still in english. 9. Log out, and log back in again as user Florence. type ls --help again. You should now see French language output. 10. type echo’ and press enter. as the command is incomplete, it will show a > indicating it is waiting for additional input. 11. use Ctrl-C to stop the command that is waiting.
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【简答题】如右下图,在长方体ABCD—A 1 B 1 C 1 D 1 中,已知AB=' 4,' AD ='3,' AA 1 = 2。 E、F分别是线段AB、BC上的点,且EB= FB=1. (1) 求二面角C—DE—C 1 的余弦值; (2) 求直线EC 1 与FD 1 所成的余弦值.
【单选题】若数据库中只包含成功事务提交的结果,则此数据库就称为处于( )状态。
A.
安全性
B.
一致性
C.
完整性
D.
正确性
【单选题】旅游团抵达饭店后,有的游客由于宗教信仰、生活习惯、身体状况等原因,提出饮食方面的特殊要求,导游人员应( )。
A.
按协议办
B.
尽可能满足
C.
给予满足
D.
予以婉拒
【多选题】有多种情况能够泄漏口令,这些途径包括()。
A.
猜测和发现口令
B.
口令设置过于复杂
C.
将口令告诉别人
D.
电子监控
E.
访问口令文件
【单选题】若数据库中只包含成功事务提交的结果,则此数据库处于【 】
A.
安全状态
B.
一致状态
C.
不安全状态
D.
不一致状态
【单选题】若数据库中只包含成功事务提交的结果,则此数据库就称为
A.
状态。
B.
安全
C.
一致
D.
不安全
E.
不一致
【单选题】对于径向全跳动公差,下列论述正确的有( )。
A.
与同轴度公差带形状相同
B.
当径向全跳动误差不超差时,圆柱度误差肯定也不超差
C.
几何公差带方向不确定
D.
属于形状公差
【单选题】根据工程勘探设计中确保人身及设备安全的概念,请回答下列供配电系统设计规范中有关电源设置的问题。。在一级负荷中,当中断供电将发生中毒、爆炸和火灾等情况的负荷,以及特别重要场所的不允许中断供电的负荷应视为()负荷。
A.
重要
B.
应急
C.
二级
D.
特别重要
【单选题】如图在长方体 ABCD — A 1 B 1 C 1 D 1 中, AA 1 = AB =2, AD =1,点 E 、 F 、 G 分别是 DD 1 、 AB 、 CC 1 的中点,则异面直线 A 1 E 与 GF 所成的角是 (   )
A.
arccos
B.
C.
arccos
【单选题】下列几何公差带形状相同的有( )。
A.
径向圆跳动与圆度
B.
圆柱度与轴向全跳动。
C.
同轴度与径向全跳动
D.
轴向圆跳动与端面对轴线的垂直度
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