How to change brightness on Linux desktop through the command line?

linux review questions

• 1. UNIX commands are case sensitive. In which case must you type them? a. all uppercase b. all lowercase c. sentence case, so the first letter is capitalized and others are lowercase d. any combination of uppercase and lowercase 2. In which order are UNIX commands given? a. name, arguments, options b. name, options, arguments c. options, name, arguments d. arguments, options, name 3. Which of these statements is false? a. Linux is compatible with UNIX. b. Ordinary users cannot change the system date. c. The UNIX operating system is called the kernel. d. You cannot change the shell after you select one. 4. In a network, all users' data and applications are centrally located on one system. a. peer to peer b. server based c. standalone d. workstation 7. Use the UNIX date command to a. display the system calendar b. display any date in the future c. reset the system date d. display the system date 8. The man program provides a. a programming guide b. an online reference for command syntax c. a file template d. an operating system version 11. What type of operating system best describes UNIX? a. a multi user, multitasking operating system b. an operating system that conducts all its operations on a standalone PC c. an operating system with a graphical user interface d. a portable single user operating system 13. When viewing a file with the cat command, you can a. edit the file b. only view the file c. spell check the file d. delete the file 14. After creating a file with the cat > filename command, if you use the command again with the same filename, you a. append new information to the file b. overwrite the file c. create anew file d. delete the file 15. The less command fixes the command's scrolling limitation. a. cat b. more c. clear d. date 18. The password should not contain a. numbers b. uppercase letters c. control characters d. the underscore character 19. The > symbol may be combined with to create output. a. only the cat command b. any command that produces output c. only the who command d. only the cal command 20. The commands display only the first or last few lines of a file. a. first and last b. cat first and cat last c. viewhead and viewtail d. head and tail 21. Multiple commands entered on the same command line must be separated by a a. space b. semicolon (;) c. colon (:) d. comma (,) 22. One major difference between the system administrator and ordinary users is a. the system administrator has unlimited permission to alter the system b. the system administrator does not have to log on to the system c. the system administrator must enter commands in uppercase letters d. ordinary users can change some system settings, but not all 23. The symbol that ordinary users see as their command prompt is the a. colon (:) b. pound sign (#) c. slash character (I) d. dollar sign ($) 29. The symbol directs command output to a file. a. * b. $ c. > d. <

• Answer:

  Hello Katauro, As mentioned in the comment, some of the questions may be misleading and many of the answers are not exactly true in all cases. To produce a proper answer, I will explain both the typical answer and some alternatives that could make that "typical" answer incorrect. If some part of this is still unclear after reading the answer - I suggest you request a clarification so I can expand on the answer as needed. [01] Case of commands: b. is the typical answer. Almost all Unix commands are created with lower case names. The more proper answer is not listed - that the case must match the file name of the command being executed. I can choose to name a program like myProgram and you would have to type its name in as I shown (all lower case would not work). [02] Order of unix commands: b. again is the typical answer but not necessarily true. The name of the command is first (at least for all the shell's I've used). Phrases after the name are processed by the command and historically have been in the order of options and then arguments. For example, on my system if I enter % ls *.txt -l a.a ls: -l: No such file or directory YAAP-v.txt yaap-k-dn.txt yaap-t04.txt a.a yaap-m.txt yaap-w.txt which indicates that the -l (long) option to ls was interpreted as a filename argument. There is no firm requirement that this order be adhered to. A command that mixes options and arguments (in my mind) is find. http://unixhelp.ed.ac.uk/CGI/man-cgi?find which has a path argument before the expression options. [sigh] [03] False statements. b. again is the most likely answer. On most Unix systems, an ordinary user cannot change settings that affect system operations. Setting the system time is one of those commands that is prohibited. I can make arguments against the other choices [e.g., Linux and BSD Unix systems are not compatible in some very minor ways]. [04] I assume this reads... In a ________ network ... and in that case, b. (server based) is the best fit. Another term for this is a "thin client" which does not have a local disk (or a very small one) and must get all its programs and data from a file server. None of the other choices imply this kind of architecture. [07] Use Unix date to... d. (Display the system date) is the most likely answer. However b. display any date in the future (or past) is also possible on the Unix system I use (use -r). Also the super user can use c. to set the system date/time. For reference, see http://unixhelp.ed.ac.uk/CGI/man-cgi?date Only a (display calendar) is strictly incorrect - use cal for that. [08] man provides... b. (command syntax) is certainly the most common use of man. However, there are sections (e.g., 2, 3) which have programming information (a) and some sections (usually 5) have explanation of file contents (c). If you want the OS version, try uname (or more precisely uname -r). [11] What type of operating system best describes UNIX? a. (multi user, multitasking) is the traditional choice. I can certainly configure a Unix system for b (standalone PC - single user). Answer c (OS w/ GUI) is not quite accurate but it is what naive users may consider correct. Answer d (portable, single user) is not quite right, it is portable but not single user. [13] viewing a file with cat b. (view the file); note the similarity of the question and answer. cat will not let you edit, spell check, or delete files. [14] Repeating cat > filename command b. (overwrite the file) is the typical answer. However, many shells have a "noclobber" option that prevent the overwrite. Refer to http://unixhelp.ed.ac.uk/CGI/man-cgi?sh for more details. Of course when you "overwrite" the file the old contents are lost (deleted) and new contents are written (created). [sigh] [15] The less command fixes the _____ command's scrolling limitation. Hmm. Depending on WHAT scrolling limitation is being described the answer is a (cat) or b (more). On a modern Unix system, less IS more [it is on the system I use...] Cat for example will dump the file to your display without stopping so it scrolls continually. The comment suggests (a) but I don't consider cat to have a "scrolling limitation" [scrolling is a function of your display device - not the cat program]. [18] The password should not contain I would say c (control characters) is the most likely answer. a, b, and d are definitely allowed (as well as a lot of other printable characters). There are some control characters that you COULD put into passwd (to set the password) but you could get into a situation where you cannot enter the password. [19] The > symbol may be combined with _______ to create output. b. (any command producing output). All the commands listed in a, c, and d work as well - just not "only" that command. [20] The ____ commands display only the first or last few lines of a file. d. (head and tail). On my Unix system there is no "first" command (but last does exist). cat prints the whole file. On my Unix system there is no viewhead nor viewtail. Use man or apropos with these names to check it out on your system. [21] separate multiple commands on a line with b. (semicolon - ;) is correct. Spaces separate arguments / options. colon (:) is a "null command" on my system. There may be a use for comma (,) but I could not find it - it definitely does not separate commands. [22] administrator and user difference a. is the historical answer. However, there are high security versions of Unix / Linux being developed where this is not necessarily true. Also note that if I bring up the system in "single user" mode, (b) also is true. This generally means you must secure access to the system console to secure a Unix system. Answer c is clearly false - see the answer to #1. Answer d is generally false (though some Unix systems allow exceptions through "capabilities"). [23] The command prompt for ordinary users Hmm. It is percent (%) on my system. Answer b (#) is what the super user gets as a prompt. The answers are all incorrect on my system, but as the comment notes - the user can change the prompt. [29] The ___ symbol directs command output to a file. c. (>) is correct for "standard output". Error messages can also be directed to a file using 2> (or other methods). As a side comment, a technique I often use is command | tee a.txt to capture the output of the command into a file (a.txt) as well as see it on the display. The other answers are incorrect. For the most part, I agree with the answers from the comment, but I believe it is important to explain WHY as well as to give you some methods to look up the answers on your own. --Maniac