1 00:00:00,120 --> 00:00:02,250 Now, let's start with biting and retaliation. 2 00:00:02,520 --> 00:00:06,810 Now every program run from a command line has three data stream connected to it. 3 00:00:07,530 --> 00:00:07,980 OK? 4 00:00:08,430 --> 00:00:14,210 The first thing which is steady in a steady out, steady error so as to the end, which is the standard, 5 00:00:14,310 --> 00:00:17,220 but this is data fit into the program. 6 00:00:17,430 --> 00:00:23,830 So this is as an input standard output, which is sorted out to output from the program. 7 00:00:23,880 --> 00:00:25,620 This is delivered to terminal. 8 00:00:26,590 --> 00:00:28,940 And we have the city, which is standard. 9 00:00:29,500 --> 00:00:30,880 This is the error messages. 10 00:00:30,940 --> 00:00:34,990 And by default, it is too it is going to terminate. 11 00:00:36,250 --> 00:00:41,320 So for the pipeline or by bank, we will use shift backs, yes. 12 00:00:42,350 --> 00:00:50,930 Which is this one, the vertical line for redirection we would use either greater than or less than. 13 00:00:51,350 --> 00:00:54,590 OK, now let's have more details about it. 14 00:00:54,980 --> 00:00:57,010 So for example, I will use the command. 15 00:00:57,110 --> 00:01:00,560 Now you can see that the last command, it would show us something like that. 16 00:01:00,950 --> 00:01:01,340 OK. 17 00:01:03,230 --> 00:01:07,160 So if I want to have this to be. 18 00:01:08,440 --> 00:01:09,760 Recorded to a fight. 19 00:01:09,790 --> 00:01:14,700 OK, so the output of the last to be recorded to a file, I would use the redirection. 20 00:01:14,710 --> 00:01:21,370 So unless then space shift greater then which means it will be the output from here. 21 00:01:21,640 --> 00:01:24,340 It will be considered in what to what. 22 00:01:24,910 --> 00:01:29,110 For example, just the text press. 23 00:01:29,110 --> 00:01:33,850 Enter now you can see the output hasn't been reached into that terminal. 24 00:01:34,210 --> 00:01:34,660 OK. 25 00:01:34,690 --> 00:01:39,770 But other than that, it has been written here now to show no such a thing. 26 00:01:39,790 --> 00:01:43,120 How know I would use the exact command I could get? 27 00:01:43,540 --> 00:01:45,820 This is the concatenation or thenation. 28 00:01:45,970 --> 00:01:55,390 Get so -- the text and it would it would show us what has been recorded, as you can see. 29 00:01:57,010 --> 00:01:58,750 The output of the last comment. 30 00:01:59,200 --> 00:01:59,600 OK. 31 00:01:59,830 --> 00:02:04,030 The same thing if I type eco double quotation. 32 00:02:04,420 --> 00:02:06,040 Hi there. 33 00:02:06,760 --> 00:02:10,210 And let's put it inside just to the text, for example. 34 00:02:10,750 --> 00:02:17,350 OK, now if I Typekit just to the text, it will show us. 35 00:02:17,410 --> 00:02:18,160 Hi there. 36 00:02:18,400 --> 00:02:18,790 OK. 37 00:02:19,300 --> 00:02:20,890 Just as we want. 38 00:02:21,490 --> 00:02:25,780 Now imagine I have this fine and I do not want to write. 39 00:02:25,780 --> 00:02:27,220 Write it over and over. 40 00:02:27,220 --> 00:02:33,560 I won't type there and I want to put more commands to it so I can put the same command as you can see. 41 00:02:33,580 --> 00:02:34,270 Hi there. 42 00:02:35,420 --> 00:02:42,800 For the second time, for example, and I would use double greater than this time, so this means that 43 00:02:43,010 --> 00:02:49,490 at the equal or the output of this command, which is high there for the second time and appended to 44 00:02:49,490 --> 00:02:50,570 that test it. 45 00:02:50,660 --> 00:02:52,610 Text this to fight. 46 00:02:53,150 --> 00:02:55,970 Now here again, just to the text. 47 00:02:57,670 --> 00:02:58,480 And you can see that. 48 00:02:58,510 --> 00:02:59,260 Hi there. 49 00:02:59,770 --> 00:03:01,390 Hi there for the second time. 50 00:03:01,570 --> 00:03:06,400 You can see that it has backslash and or a new line. 51 00:03:08,120 --> 00:03:14,810 Because by default, the eco command, it will bring less and it is considered backslash, end and backslash 52 00:03:14,810 --> 00:03:16,160 and means a new line. 53 00:03:16,430 --> 00:03:23,630 Now I can choose another thing which is using Dash E to skip the thing. 54 00:03:23,630 --> 00:03:24,800 So this is not to print. 55 00:03:25,670 --> 00:03:33,290 This is to put backslash whatever thing here, and you can use the end command so any and do not print 56 00:03:33,590 --> 00:03:36,200 backslash and so it will not print a new line. 57 00:03:36,530 --> 00:03:38,360 By the way, how did I know about it? 58 00:03:38,720 --> 00:03:40,130 Again, just open it. 59 00:03:40,340 --> 00:03:46,820 And here you can see all the options from the menu at Beach here and do not artwork detailing New Line, 60 00:03:46,820 --> 00:03:54,590 which is backslash n e to enable interpretation of backslash skims like backslash e backslash. 61 00:03:54,590 --> 00:03:55,080 Whatever. 62 00:03:55,100 --> 00:03:55,580 OK. 63 00:03:57,440 --> 00:04:03,260 Well, I'm assuming that you are familiar with these, if you are not, you can read more about it or 64 00:04:03,260 --> 00:04:03,950 you can ask me. 65 00:04:03,980 --> 00:04:04,580 No problem. 66 00:04:05,300 --> 00:04:07,460 OK, now let's quit from here. 67 00:04:07,640 --> 00:04:10,790 Now this is for the greater than the redirection. 68 00:04:11,060 --> 00:04:14,520 Now what if I want to redirect from a fight? 69 00:04:14,540 --> 00:04:21,380 OK, so the great then, as we saw that it will bring the output of the LSD and convert it to the text 70 00:04:21,560 --> 00:04:24,020 and will do is double that greater then? 71 00:04:24,020 --> 00:04:25,520 Which means appending. 72 00:04:25,790 --> 00:04:34,940 Now, if I want to read a from a file, so for example, I will use the command WC now men w see. 73 00:04:34,940 --> 00:04:39,530 You can see this is to print new line word and bytes count for each fight. 74 00:04:39,800 --> 00:04:41,500 So this is for word count. 75 00:04:41,510 --> 00:04:43,280 It stands for word count. 76 00:04:43,580 --> 00:04:43,970 OK. 77 00:04:44,300 --> 00:04:46,310 So if I type word count? 78 00:04:49,240 --> 00:04:51,790 And the twist to the text. 79 00:04:53,740 --> 00:04:58,330 It will show us like the following that this this fight has to. 80 00:04:59,480 --> 00:05:03,650 Lines it and eight letters. 81 00:05:03,920 --> 00:05:04,340 OK. 82 00:05:04,490 --> 00:05:05,510 How did I know that? 83 00:05:05,690 --> 00:05:07,700 Just the men you see. 84 00:05:07,880 --> 00:05:09,950 And here you can see it with Brent in your line. 85 00:05:10,040 --> 00:05:10,330 What? 86 00:05:10,340 --> 00:05:14,450 How, however, how much line we have, how much work and how much bike counts. 87 00:05:14,710 --> 00:05:19,730 Or, by the way, the character itself consider to be a bike. 88 00:05:19,940 --> 00:05:23,180 So buy it here means that character. 89 00:05:24,160 --> 00:05:24,580 OK. 90 00:05:25,150 --> 00:05:32,680 And for this, we can use more options like that, see for the character dash, for the car's dash and 91 00:05:32,680 --> 00:05:35,140 how many lines and whatever they do for words. 92 00:05:35,500 --> 00:05:45,340 So if I type W. see Dash W four word and twist to the text, this will show us eight words inside the 93 00:05:45,340 --> 00:05:45,840 cat two. 94 00:05:45,850 --> 00:05:52,090 So if I can't hear, you can see that one two three four five six seven eight as you can see it worked. 95 00:05:52,390 --> 00:05:53,500 OK, cool. 96 00:05:53,830 --> 00:05:54,550 So far, so good. 97 00:05:54,580 --> 00:05:56,370 Now we learned what is WC now? 98 00:05:56,380 --> 00:05:57,010 What is there? 99 00:05:57,010 --> 00:05:57,760 Is addiction here? 100 00:05:57,820 --> 00:05:58,270 All right. 101 00:05:58,360 --> 00:05:59,740 So it is clear this came first. 102 00:06:00,010 --> 00:06:01,270 Now W see again. 103 00:06:01,540 --> 00:06:08,980 Dash W now this time, as you can see, we booked for the WC command a file to read from, right? 104 00:06:09,520 --> 00:06:15,160 Now what if I want to read from a specified using the redirection? 105 00:06:15,190 --> 00:06:24,520 Not like that so I can use the list then, which means that this w c command needs an input and get 106 00:06:24,520 --> 00:06:28,630 that input from what file, from text to the text. 107 00:06:29,350 --> 00:06:33,460 OK, and it will show us again the same thing. 108 00:06:33,820 --> 00:06:39,850 By the way, if you notice we have a different output because this is using the redirection. 109 00:06:40,000 --> 00:06:41,230 But here it. 110 00:06:42,260 --> 00:06:47,850 Brent, the eight character or eight word and the name of the flight. 111 00:06:48,480 --> 00:06:51,230 Yes, so you can see that the output is different somehow. 112 00:06:52,240 --> 00:06:59,480 OK, now what if I want to redirect the steady error, so clear the screen? 113 00:06:59,740 --> 00:07:04,570 Now if I type this comment, you can see that it would show us command net fine because this is just 114 00:07:05,320 --> 00:07:09,250 an arbitrary example or arbitrary command not found in very light. 115 00:07:09,610 --> 00:07:13,010 Now what if I want to to see if it is not found? 116 00:07:13,030 --> 00:07:14,810 Please don't show the error on that. 117 00:07:15,160 --> 00:07:20,050 And for that, we would use something called redirection that I see the error. 118 00:07:20,350 --> 00:07:21,010 So tool. 119 00:07:22,240 --> 00:07:22,870 Which is. 120 00:07:24,060 --> 00:07:25,780 The study, by the way. 121 00:07:26,620 --> 00:07:31,320 Zero considered study in, but one considered to study. 122 00:07:32,360 --> 00:07:36,290 Output and to consider the city or the standard. 123 00:07:37,890 --> 00:07:38,250 OK. 124 00:07:39,090 --> 00:07:47,070 Now I knew there is a lot of information here, but just for me, so too without any spaces redirection 125 00:07:47,520 --> 00:07:48,780 to that slash device. 126 00:07:49,860 --> 00:07:51,210 Slash, no. 127 00:07:52,700 --> 00:08:00,230 Now here at this, the this is just another boy in town, it will point to nothing. 128 00:08:00,710 --> 00:08:04,940 So run this command and see the era, which is this one. 129 00:08:05,920 --> 00:08:09,620 Go and let it go to be inside here. 130 00:08:09,770 --> 00:08:10,220 Dev. 131 00:08:10,220 --> 00:08:10,580 NULL. 132 00:08:10,820 --> 00:08:13,280 Which means don't bring the on here. 133 00:08:13,790 --> 00:08:17,620 What did he there and then not here, which is just a void. 134 00:08:17,690 --> 00:08:18,330 Nothing here. 135 00:08:18,650 --> 00:08:19,720 OK, so enter. 136 00:08:19,730 --> 00:08:27,500 You can see that this time the command that the command not found here, nor has it been put to the 137 00:08:27,530 --> 00:08:35,750 terminal because we redirected the standard error to be to the dev null, which is to the void of the 138 00:08:35,750 --> 00:08:36,140 system. 139 00:08:36,590 --> 00:08:40,770 Now what if I don't again get this three? 140 00:08:41,179 --> 00:08:43,039 The text, by the way, is the three. 141 00:08:43,039 --> 00:08:44,150 The text is not found. 142 00:08:44,570 --> 00:08:46,580 As you can see, no such file or directory. 143 00:08:46,910 --> 00:08:49,730 Now, how should I print this? 144 00:08:49,820 --> 00:08:55,800 And if there is no such file, I do not want to to be outwitted, to be printed to that terminal? 145 00:08:55,820 --> 00:08:56,690 How should I do that? 146 00:08:57,500 --> 00:08:58,610 Yes, you are correct. 147 00:08:58,940 --> 00:09:00,170 As we learned previously. 148 00:09:00,470 --> 00:09:02,390 So get this to read the text. 149 00:09:02,540 --> 00:09:08,810 It is not fine if it is not found, but two or the standard error to be inside. 150 00:09:08,810 --> 00:09:09,430 Dev null. 151 00:09:10,870 --> 00:09:12,730 And you can see, you guessed it right. 152 00:09:13,090 --> 00:09:14,500 And it is working correctly. 153 00:09:14,830 --> 00:09:21,730 OK, now enough with the redirection, we learned that a dietitian greater than the greater than and 154 00:09:21,790 --> 00:09:22,570 less than. 155 00:09:22,840 --> 00:09:27,490 And we learned how to redirect their stand up to the dev null. 156 00:09:27,730 --> 00:09:30,640 So the error will not be printed to the minute. 157 00:09:31,180 --> 00:09:33,070 Now it's time to talk about biting. 158 00:09:33,490 --> 00:09:40,680 Now, as we learned by being, is using the vertical line shift backslash, OK, or whatever it is and 159 00:09:40,690 --> 00:09:41,440 your keyboard. 160 00:09:43,080 --> 00:09:44,880 Now, for example, if I get. 161 00:09:46,970 --> 00:09:48,230 This to the text. 162 00:09:50,420 --> 00:09:50,900 OK. 163 00:09:50,930 --> 00:09:53,270 You can see that it will start showing. 164 00:09:54,020 --> 00:09:54,800 Hi there. 165 00:09:54,830 --> 00:09:56,810 Hi there for the second time as we looked. 166 00:09:57,230 --> 00:10:03,260 Now what if I want to count that number of words for this fight? 167 00:10:04,200 --> 00:10:08,430 I would use pipe or, as we learnt, using the WC command. 168 00:10:10,010 --> 00:10:14,150 Using the redirection or WC dash for the fight itself. 169 00:10:14,360 --> 00:10:18,740 But there is another way to do it, by the way, using the pipeline. 170 00:10:19,220 --> 00:10:26,720 So get this to the text and the output with the pipeline means the output of this command will be considered 171 00:10:27,020 --> 00:10:28,250 in both for this command. 172 00:10:28,550 --> 00:10:34,250 So this to the text and the output of this, which is the high they're high, therefore is the second 173 00:10:34,250 --> 00:10:39,020 time would be input for the another command, which is the ability that's W. 174 00:10:39,290 --> 00:10:43,940 OK, now if I do that, press to us it is working correctly. 175 00:10:44,150 --> 00:10:45,740 So the output here. 176 00:10:46,640 --> 00:10:48,980 Considered to be in, but for this moment. 177 00:10:49,100 --> 00:10:52,610 OK, so this is what pipeline means, OK? 178 00:10:52,730 --> 00:11:00,410 By the way, we can treat addiction again and again using by blinding, so kept this to the text. 179 00:11:01,740 --> 00:11:07,110 And by blinding and output will be considered input for this and again, put this to be. 180 00:11:08,510 --> 00:11:11,120 Result the text, for example. 181 00:11:11,960 --> 00:11:14,990 And if I type, as you can see, OK to text here. 182 00:11:15,230 --> 00:11:17,240 Get it to see what is inside it. 183 00:11:17,240 --> 00:11:19,820 Yeah, it is walking one hundred percent. 184 00:11:21,450 --> 00:11:21,880 All right. 185 00:11:22,260 --> 00:11:23,070 So far, so good. 186 00:11:23,640 --> 00:11:27,120 Now again, I recommend you to practice with me. 187 00:11:28,460 --> 00:11:34,430 And practice what you have learned on whatever values, I would provide more exercises. 188 00:11:35,390 --> 00:11:40,970 And the assignment for a simple exercise is just to practice what we have learned here.