 Now, we are coming to one of the final topics of using Linux tools. Many people had been asking about editors. So, we will first see Nano, we will see a little more of Nano, we will see G edit also, then we will see Vem. Vem I would like to say is the best, that the close competitor is far behind. So, why do not we see Nano, Nano filen Nano test dot txt, extension you will choose depending on the purpose. So, we are writing, we are beginning to write, write a new file, enter for next line. If you go on typing on the same line, then it will not put enter by default, it will hide all those into this dollar character, this dollar character in Nano. We will say there is much before this also, there is just some way to represent it, dollar has not actually come into the file. After you write all that press enter. Now, it is only showing one line at a time, again it says there is this dollar means there is some extension. It is there, it is just that it is not showing it to you. You might choose some wrap line option, etc. So, as it shows, do not worry about it, the file is intact. It is exactly the way it will put a enter only when you press enter. If you do not press enter, it will just go on putting and it will hide unnecessary things inside a dollar like it is hiding here. After you do all that, you can do control X. What all to use? Those options are there here, because Nano is one of the first things to learn. They all those comments are always below. Control O for write out, write it, write all this to a file. If you want to cut a line, cut line means what? It says control K. Control K will cut the line, control U, then uncut it right there. But you might want to uncut, you have to paste it somewhere else. You can paste it again and again. So, this is how you use a Nano editor. One can do many advanced things for quite a few years, I use just the Nano editor. It is at least as useful as Doc, let me tell you. You can do copy, paste, everything that is possible in open office, copy, paste or Microsoft Word copy paste is possible in Nano also. But this is a simple text, plain text editor. Whatever is written in this, why do not we save and came out, whatever has been written is plain text. That is why we can see using less. We can see grep, we can use grep on this. It is a plain text file. That is what all your shell scripts, your Python scripts, Latex, all are required to be plain text. They should not have been written in any fancy program package. These plain text editors, we will not like to call it a package. It is best called as a plain text editor. But this open office or Microsoft Word, these are all some fancy packages. To read that particular file, you need that package only. You cannot do command line grep, cut, paste to fish out the information that is required. For example, let us, I do not even know what word was put. There is a new word. Word new was there inside this, grep new. Here, this is the line with the word new. Because this particular information was written in a plain text editor, grep, cut, paste, cat, concatenate requires, all of that requires it to be plain text editor. Cat might concatenate even if it is not a plain text, even if it is not ASCII. For it to be visible on the screen using cat, it requires to be plain text. What is de-edit now? Why do not we continue to edit the same file? The fact that you can use a different editor to edit the same file is because finally the text is a plain text file. It was written by any editor no longer. This plain text is the only one that is Unix, Linux, Mac, DOS, Microsoft Word, Microsoft, any operating system, plain text will be compatible. That is why it is very universal. Also file sizes are very small. So now we open the same file using de-edit. De-edit does not even know that previously when you wrote this file you had used nano. It will not complain. Now all these other fancy packages complain that this was built using some other package is not made for this. Here, plain text editor, we have opened this in de-edit. De-edit allows you to use the mouse. Now we can copy it like this and we can copy another word and we can right click it and cut, copy. You can do various things. You can go here and control V for paste just like the commands that you are used to. You can also go here, another place and you can paste it. The mouse is all very much accessible. De-edit is a very simple helpful editor. It is simple. That is why you cannot do many complicated routine things. Any questions about this? So you can have a look. I do not use de-edit. I cannot tell you various nice things it can do. For those of you who use de-edit can help us tell all these things. It appears like you can edit multiple files. Open multiple files as different tabs. You can open a new one. You can open new one here and copy one file and another file. You can copy here from this one. We have copied. Then we can go to this one and we can paste here. Control V for paste. Also you can right click. You can right click for paste. So we encourage all of you to use plain text editors whether you use nano or de-edit or vim or emacs. We will not bother you. For turbo, you will give zero marks. If you do not give a turbo or TGZ file, you will give zero marks. But what editor you use is completely up to you. Same file you can open in notepad or in wordpad. Some of these end of the line characters for wrapping, etc. It is important to know that wordpad is the one that opens more properly in Microsoft. When you are working in Microsoft Windows, the same file can be very much opened there. Do not worry about compatibility issues when you are dealing with plain text editor. So that finishes g-edit. We will spend a few minutes on vim before we take up questions. So now why do not we just quit this? It will say look all these are, we are not interested in saving it. You can also save it and quit. You can save and then quit in g-edit. There is some file we wrote. We have now opened an editor called vim. So whatever I am going to explain now is about only the vim editor. Those of you who are not interested in vim editor can now start spending time on various exercises in the slides that we did not pursue. For for loop, if while those exercises in the slides we did not pursue, you can get started with that directly. If you are happy with g-edit or nano editor, you can get started with that directly. If you are interested in vim editor, then you can spend a few minutes now. It might appear very difficult. But believe me, I will show you how you can do really complicated things in a very quick way. But if you feel it is too difficult, do not worry about it. Do not blame Linux in any case. It is vim editor that is complicated. Do not blame Linux for vim being difficult. Vim is a purely personal choice. I understand it is very difficult for initial users. But you can do many complicated things very easily. Once once somebody masters it a little. It takes 3-4 hours only to master the basic things. So let us go to one of those one of those files where lot of lot of commenting had to be done, block commenting. That also was not done. So here was, why do not we suppose we have these, we decided to remove the colors. So here is our while x.sh file that we had seen before we broke for lunch I think. Now if you want to comment, there is no block comment. If you want if you want to comment this entire part, then it is not, I think it is not possible to go in the start and say hash hash from here onwards up to up to here. Such a thing is possible in C C plus plus. I think it is not possible here. If it is possible, we let you know on moodle. How will you comment this entire thing that we had block, we had whatever is highlighted. One thing to do is go here, yeah again come here, again come here, yeah. If you have to do this block thing, you have to put a hash in the first line, first character of every line. Not necessarily first, the first non-space character has to come as hash. This is multiple line if you have to hash the entire block, you have to put a hash on every line. This you can do actually by going in G edit, G edit, you can go to the first character, put the hash there. If you are unhappy with typing the hash each time looking at the keyboard, you can copy it once like that in G edit, copy it and then again take the mouse each time to first line and paste, paste, paste, paste, paste, paste, yeah. So, first of all let me tell you, even hash I did not spend any time, yeah. So, wherever we are beginning of the line, this is how I did. Even easier, if there are more lines, so I can just copy like this, yeah. Let us copy the entire like this. So, there is some vi syntax, yeah. We will cover in a few minutes some basic things. I am trying to motivate how it is very easy to do all these complicated things. Search replace for this entire patch, replace the first the begin line character with hash, yeah. It has performed all of this in one go. If there are many lines, if there are thousand lines, all those thousand lines can in one go be done. What is one go about it? I press colon once and typed this long thing. That is all, yeah. As soon as I typed, it has done again. If I want to undo, you for undo all of them, again you all of them are done. So, you see that if you want to do many, you see in things, if you want to navigate in the file, then we all spend so many hours per day editing a file. For example, it might be editing a email that we have to send. It might be editing a program. The program might be a tech file. It might be a latex file that we are editing. Given that we spend so many hours per day, why should we not learn some really powerful editor and make our life easier? If we have to comment, why not use a very strong powerful editor like vi and do everything more efficiently rather than copy, paste, one by one, hash, hash, hash, yeah. So, I took this very simple example of multiple line commenting, but almost anything is really easy in vi, yeah. That is why we spend a few minutes on vi. So, we will put up some slides about benefits of vi, how to use it on Moodle. Important thing to remember is when you start vi, all these keys, when you type, they are not going to come on the screen. They are all commands, yeah. So, we are now speaking of commands inside vi. These are not Linux commands, which we have learned since yesterday morning. These are all commands within vi. We have already opened this particular window. There is no command prompt. This is not Linux. This is not bash shell. This is not command prompt. There is vi editor for DOS. There is vi editor for Microsoft Windows. There is vi editor for every operating system. We are not dealing with command prompt anymore. As far as this vi is concerned, command means what you are doing inside. Inside the vi command, h is for moving, moving left, l is for moving right, jkl, yeah. All these commands are for just most of them are for navigating, yeah. w for moving to next word, yeah. Control f for moving to the next page, control b for moving to the back page. So, most of the commands, most of the keys now are commands. Only some of these are for going to a different mode, where we start inserting all this information. For example, if you have navigated enough, if you have navigated to one's heart's end, why do not we start putting in some text, yeah. One way of putting the text is going into insert mode. So, till now we were in command mode. Whenever you open vi, you will automatically be in command mode. And if you are in command mode, nothing is at the bottom, yeah. So, when to come back to command mode, from wherever you are, just press escape several number of times. If you are on command mode, see please notice at the bottom here, there is nothing written there. At the bottom here, whatever is highlighted in black, nothing is written there. But if you go to insert mode, for example, by pressing I, sorry, by pressing I, we have gone to insert mode. Immediately this place that I had highlighted, it says look, we are in insert mode, yeah. So, now as soon as you are in insert mode, you can start typing various things. Now, all the keys now are suddenly no longer commands. They are all, when you type, they will come into the screen, they will come into the file, enter, etcetera, yeah. So, I am giving a loose chance to my fingers to go on putting whatever they want. You can type more meaningful words, I am sure. So, all this has come in. After you have put in enough characters, press escape to go back to command mode. Press escape a few times extra, do not worry about it, nothing will go wrong. Inside the VI editor, escape means coming back to command mode. If you are already in command mode, it will again come back to command mode. Nothing is different about it. Now, all the keys are again for navigation, yeah. So, right now I am pressing H, J, K, L for navigating. You can also use arrow marks, yeah. You may not know what keys I am pressing, but whatever keys we press, they are most of them are for navigation. Now, we might want to delete a line, double D for delete, another D, yeah. If you have done some complicated editing, then dot will just do the same thing again. What I am doing is I am just deleting one by one all of these. U for undo, whatever you did, it will undo it. It will again put all these back. Finally, after you have edited everything, you want to save it and quit out, yeah. First, quitting colon WQ, yeah. So, please note, all of you should know how to open a file, how to go to insert mode, type various things that you want. Press escape to come back to command mode. Whenever you start the file using WIM, it will default be in command mode. After you do whatever editing you want, escape will bring you to command mode again. And after you are in escape, colon, to press colon means you have to press shift colon, that will bring the cursor down to the bottom. From wherever you were, the cursor will come to the bottom and WQ will quit out of this. It has written that file to while dash x dot sh. And now we are back to the Linux prompt. In the Linux prompt, notice the previous command we typed was WIM. WIM, I am not sure whether we have asked all the computers to have WIM in the various centers, yeah. WIM. If you are using our CD, then WIM also will be there. So, WIM will be there, very likely you can also do hands on or whatever I have told. Now, we can again do WIM and again we can open that file and do various editing. One can do various things. In particular, let me at least tell you how I did this block editing, block commenting. So, I used v for visual mode. As soon as you press small v once, now you can use your cursors to mark the patch, whatever patch you want some work. After you are marked, press colon, that part, whatever your mark comes down as some symbol. That says that is the marked pattern. For the marked pattern, s small s for substitute, s for search and replace actually. Search and replace hat, hat for beginning of the line. Important thing to note is, if you have spent so much effort in beginning of the word, end of the word, beginning of the line, end of the line, all syntaxes are available here also. They are the same. Underline grep, they are all very closely linked. That is why you do not have to remember hat for beginning of the line character. It is not different in Vi nor in the Linux prompt. They both are the same. Now, we are going to replace this with what? Hat. If you replace actually the begin character will not get lost. It will continue to be there. Put a space also. There is search, search and replace only over this particular region, whatever region has been marked. In this case, replace this pattern, search and replace with this pattern, with hash. And now, when we press enter, that will have effect. That is how we did this. After we do this, colon, again it brings a prompt below, it brings a cursor below. W for write, write and quit. Write and quit will exit, exit after writing. If you want to just quit, you can do this. But it is look, you did not save your work. It is telling you did not save. No write. If you want to quit without writing, then you have to force it. Queue exclamation mark, one minute. Queue exclamation mark will help you quit without saving the file. This is in short about WIM. Details about WIM, we will put up a nice presentation by a person called Ananya Sain. He has kept his PDF file on the web. We will send you the link. So, let us see what is typed here. So, whatever about WIM is not been prepared really like a slide. It just happens to be here. So, perhaps that is why this is also not there in the Moodle slides. For another piece of information, something called site, some of you asked about a good editor and for that Shikhand answered site. Site is a source code editor and has also many, is very powerful. Both WIM and site will let, will highlight the syntax. Depending on the extension, it knows this is a tech file, this is a SH batch file or this is a python file. From the extension, it will guess that this, these are all commands because this extension suggests that it is a python code and from the extension, it will automatically give nice color to the syntax. Let me give you an example. So, let us see WIM num check dot SH. So, all these colors are not there because the colors are not visible. Why do not we again bring back colors into our lives here? This is showing that this is a command. I can understand that this yellow color is not visible on the screen there. For that purpose only, I have disabled all these colors by setting, going to some different term. So, on your own computer at least you can keep the colors and you can see that all these different syntax gets highlighted from the SH. We can also see a quick tech file. Here is a tech file. All these commands are showing in different, different color. All math is coming in different color. This is an example of how VI, just like site, just like site will allow you to do syntax highlighting and that syntax highlighting is done very intelligently. It is done depending on the particular language you are doing and that language is guessed from the extension. If there are any questions, we can take the questions now. Otherwise, we want everybody to practice those problems that were there in the slides for if, for and while loops. Are there any questions? Somebody has asked how to say file in WIM if name not given as command line variable. That is one thing we can answer. How to change default permissions for every new file being created. This is already somebody helped yesterday as uname. Uname is the one that one should use for this purpose. For bash, somebody has said you can use three codes for multi-line and again put three codes for end of the bash. Does Anindya know this? Anindya has just now walked in here. Not as a participant. To participate in this would be very trivial for him. He happens to be here for a different purpose. So, let me ask him that in bash, we are trying to explain about bash and we put hash as a command. So, for multiple lines in C, you can start that from here. This line onwards should be command until something else comes. Do you know what to do for bash? So, he does not know but somebody here has told, somebody from INCC Pune has told that you use three codes, three single codes I presume to do this. This is really useful information. I encourage people to try this out and it is good for us also to know this. Are there any other questions? No audio video. Only in one particular center. How to create tar from files of multiple format? Tar will just create all the files in that directory, that sub directory, whatever you specify. It will not even worry whether the formats are same or different. So, that is why we do not have to worry about multiple format or same format. Now, somebody had asked how to save also including files with tar. So, the same question has asked, same person has asked, can we create a tar ball which itself has, can we create a tar ball of a directory and the directory itself has other tar files? Yeah, why not? Tar will not worry about it. Only that the file size will become very large except for that tar does not have a problem. So, if we say WEM, we have just opened WEM, plain WEM and we can type various things. Now, when we do WQ, it says we did not specify any filename when we started WEM. So, we can do W filename. Now, it will allow us to quit. Let us see the most recent most file that was created. So, where is this file that has got created? LS minus ALRT I did. I did, it has, the filename has come now. I think I typed something wrong. So, filename is the recent most file that we created by choosing the filename from within WEM. Any other questions? Difference between tar minus C, V, Z, F, C, V, F, Z. Somebody has asked the difference between whether the options, if you give the options in different sequence, whether it matters or not. My guess is that does not matter, but you take this yourself. One thing one can check oneself. If there are no more questions, then I recommend each one of you to start with the various exercises. Why? Because our test today will require you to have tried them all. You please try them all and ask us questions as soon as you can. Triple course is not working is what Srikant here told. There is one other resource I forgot to tell you. So, there is something called WEM tutor. WEM tutor is a command. You run it and as you read, it will tell you various commands. It says approximate time required to complete the tutor is 25 to 30 minutes only. So, if you spend little more time, it will take little longer. WEM tutor is ideally, it is a WEM file actually. Inside this WEM file, you can edit it. While you see, you can edit it also. And you quit out of it, just like you quit out of WEM. So, we will send you a link of the presentation file that Anish Sainath prepared, which is kept in his homepage. So, if there are no more questions, then we can start with exercises. There is a question from VIT Vellore. Sir, actually I did a program to find the bigger number among given two numbers by using command line arguments as input. It do that program gives the output as the right one, but I cannot add the two numbers. Suppose for example, that the program I executed with the command line argument as a three and four, it will give that four as a big number, but I cannot get the result as a three plus four as seven. How can I get it, sir? Yeah, thanks for your question. You see, in Bash, we can compare two things. See, which is larger, which is smaller, but how to add them is something I have not done before. But I really want to learn how to do this. And we have not covered this in the course. Incidentally, Prashant is the person who knows this very well. And he will answer this question. Hello, ma'am. To add two numbers in Bash, you have to use expression or let. So, like expression A equal to dollar B plus one where B will be some other variables. So, this way you can add these two numbers. But you have to use extra syntax that is EXPR at the beginning of that thing. Or other way of doing is defining each like let A equal to something and let B equal to something and then adding using let C, let again. So, you can try this out. I will send you a particular example on modal also if you want. It should be in quotes actually at the beginning of the line. See, we will just check this and tell you. It is some small syntax very close to what is written, what is visible. So, very soon Prashant will check this and answer back to you. So, one can add only integer manipulations allowed. Add, subtract, divide, multiply. This he will tell in a while. So, the next question is from Ufa Khamja College, Hyderabad. Please ask. Good afternoon sir. I exhibit this simple C program in Linux as well as Windows. But output is different. Why sir? So, his question is that there is a simple C program whose output is different in Linux or Windows. It is hard to say without seeing the program. Perhaps Windows compiler is not working properly. No, if you tell the program I will not understand. You please send it on modal, not now in the evening. Anyway, it is many years since I did any C programming. You please send it. Any other questions from Ufa Khamja? Hello. Yeah, the answer for that EXPR is it should be written as A equal to backcodes A equal to, A equal to backcodes EXPR space to space plus. Please tell slowly. No, EXPR should not come first. It should be A equal to. A equal to backcodes A equal to backcodes EXPR space for space 5 plus 5 backcodes. Okay, thank you very much. Thank you for participating from there. Yes, very good. It is indeed adding as expected. So, the syntax is now I know the syntax. Thank you very much. Any other questions from Ufa Khamja? This shell is not available. So, how to add this shell in our system? Can you please repeat the question? How to add C shell or con shell? Sir, other shell, we are covering. Sometimes when we try to run the shell script using C shell or con shell, one which is not the default shell. I do not know. So, how to add these shells in our login? Okay, thank you very much for your question. So, the question is instead of C shell, if you have K shell, if you instead of bash, instead of K shell, how do we do these other shells? I think this KSH, let us go to this. KSH is not installed in this. So, it appears like these other shells are there. ZSH is also not there. So, you just run that ZSH will go to that. So, in my computer, these shells are not installed. But if you install, then just write TCHSH will go there. For example, just type bash, we are running into, we have gone into another bash script. We have gone into another shell within our earlier shell. You just type ZSH and you would have gone into that, provided it was installed. But then we are not going to spend time on other shells, only bash. So, now that you asked, I answered this. After you installed these other shells, just type ZSH will go there. At least SH might still, SH is there. You can see what all shells are running. So, SH is another shell that is running now. But do not worry about the other shells. Please learn using Linux tools and just bash nicely. And you will have learnt much already. And you would already be very effective. Okay, the next question is from College of Engineering, Bharamati. Can I get output of one shell script into another shell script? Yeah, yeah. Yeah, the output of one command can very much come on the screen. If it can come on the screen, it can be taken as input to another command. Maybe pipe is not really that. One can write functions in bash. Yeah, and the output of that function is what can easily go to another function. So, this is very much possible. Yeah, we have not seen an example on this. But this would be an advanced topic. I do not know how to do this properly. One has to use something called function in bash to do this. Somebody has asked one chat. Tell me in the command to search all files having any specific word. Yeah, so this is something we saw once and very useful. Why do not we search through all the files? Here they are. So, all these files, inside all these files, we inside this list of files, we would like to grab for an, sorry. Yeah, so what has this done? An character, an pattern is being searched through not just one file, but a whole list of files. That list of files is getting generated using the find dot command. Yeah, why? Because find dot command, when you do find dot, it just lists all the files, directories, sub directories, files, inside sub directories, everything it will just spit on the screen. Instead of spitting on the screen, we want that to go as input to something else. This incident is list of files. So, why do not we grab through a pattern, grab for a pattern through all these files. That is what this back quote, open quote is doing. So, it has given all this. Does this answer your question? Dot. Find dot minus name. Now you give an. An. The an. Whether an is part of the file name. Okay. This will work for txt. It will give us all txt files. Txt is not there surprisingly. Yeah, stars. Star is also required. Yeah. So, or sh. Yeah, it will give you that pattern is there in the filing. Yeah. Somebody is asking, explain the usage of scd. Scd is very, if you know when scd is not hard, you already when is outside the scope of this course, so would scd be. Yeah. I would say scd is very useful. We will not discuss more than that of scd. There is a question from Jaipur. Please ask. Hello. Hello. Sir, you mentioned slide number 80 with option x. How could we expect files within Archive? Hello. Yeah, we are able to hear. We heard your question. Archive. How to extract files within the archive? With hyphen x. Capital x. Capital. Small x. I do not think you can extract only one file from the archive. It will extract all the files from within that archive. This x means you extract all the files out of that archive, not just one file. To the best of my understanding, you need, you will extract all the files. Yeah. So, I forgot to tell one important thing when I was explaining Tarball. See, compressing a file, compressing a collection of files into one file and then compressing it, extracting out such a straightforward thing, but still you need some licensed packages for Microsoft Windows. It is really disappointing that such a straightforward thing and Winzip, why should Winzip be licensed when it is such a straightforward thing? Compressing and uncompressing, so many algorithms are there. So, I really want that each one of you should stop using Winzip to begin with. Then you should stop using Microsoft Windows also, but that is not as urgent. So, Tar, compressing, uncompressing, so straightforward, extracting out from an archive. So, any other questions? Yes, sir. Sir, can you please explain hyphen v? The v option is only for verbose. Verbose means those who give too much information. Too textual, too much unnecessary information. So, verbose, you might be interested in verbose because you might be concerned whether something has become okay or not. You just, whether you put the v option or not, do not worry about it. Do not worry about the verbose. Let me repeat and be verbose. Do not worry about verbose. If there are no more questions, we will take this question on chat. Is there no more questions? Before we go to this question to Saint Joseph College Kerala, so there is this question about RAR. I think WinRAR is free. There is, I think, I am not sure, but you can install RAR and UNRAR packages on Linux and it will run. RAR and UNRAR can extract out RAR extension files. So, RAR and UNRAR are commands one can install separately. Tar is of course a GNU one that is default there. So, you can uncompress RAR archives. Okay, the next question is from Saint Joseph College Kerala. Lab environment, we need to copy files from one system to another. Usually to students, we will prepare one exercise and distribute among system. How can we transfer the files from one system in Linux to another? Okay, yeah, that is a good question. Any other question from your college? We will take up all the questions and then start answering. Okay, sir, we also want to take backup into CD. So, how can that can be done in command interface backup process? Yeah, taking backup is very important. I am sure all of you should be able to do backup. Shrikanth will come and help us about that. So, how to copy from one server to another server? That is what I know. That is what I will tell. So, right now no other computer is connected to this because of SCP SSH is for logging into another server. Bairav happens to be some other server in our campus. It is not connected, unfortunately. But if Bairav is connected, one can copy file from here to Belur login inside directory there, file name, file name there. Yeah, this is some syntax. SCP is a secure copy. Nowadays because Telnet and all is not allowed for security reasons. It is not encrypted, I think. So, SCP means secure copy. Secure copy from one source to another destination. Either source or destination now can be across computers. You have to give the exact name of that server. Maybe you have to give IP address. My computer already knows the IP address of this server called Bairav. Some Bairav is some name inside IIT. So, you have to give IP address if it is another computer. If it is on LAN, IP address, etc., is the same. Whether it is Windows or Linux, you address that same computer by that IP address and you have to specify. That computer has to also be a SSH server, not just a client. While this server, this computer can be a client. So, after some server client relation and all is established, one can copy files across servers, across computers. Now, coming to this topic about backups in Linux. That is something Shrikanth can come here and answer. Regarding backups, we have many tools in Synaptic Package Manager. So, I do not want to mention the tools name exactly. You can search as a backup tools. There are many command line backup tools and GUI based graphic backup tools. And what was the other question? DVD, CD writing, CD writing things. So, we have many CD writing tools on Linux. So, K3B, Bracero, they are popular among GUI tools. And we have command line tools also. So, but predominantly we can use K3B or Bracero. They are very good and we can do all kind of DVD writing and CD writing functionalities with these two tools. So, is this answer the question? So, this is the plan for today. So, we have skipped certain slides because they were supposed to only be seen from the slides and put on a editor, use nano as we suggested and execute them and check. But then it is important that you do this for doing well in the test. And you doing well in the test is very important. Only those who do sufficiently well will pass the course. Only they get this participation certificate.