1 00:00:01,030 --> 00:00:08,860 What is exist that those exit status is a numerical value which can tell us if previously called script 2 00:00:09,190 --> 00:00:13,970 or previously executed command was successful or not. 3 00:00:14,320 --> 00:00:21,370 We can get this value by printing value of dollar sign and question mark disvalue is being called Egli 4 00:00:21,380 --> 00:00:25,340 status if his status equals zero. 5 00:00:25,390 --> 00:00:33,560 It means that previously quoted command or script was successful if the status is some non-zero value. 6 00:00:33,850 --> 00:00:40,010 It means that previously is a coded script or a function or command was finished. 7 00:00:40,560 --> 00:00:44,630 Or did it means that something finished on it. 8 00:00:44,680 --> 00:00:47,130 It basically means that something went wrong. 9 00:00:47,410 --> 00:00:52,270 That there is missing argument in the script that some file which should exist doesn't exist and so 10 00:00:52,270 --> 00:00:53,080 on. 11 00:00:53,350 --> 00:00:59,950 Important is to know that when we are creating script we can exit it using exit command. 12 00:00:59,950 --> 00:01:07,660 That means that descript will be exited immediately and other alliance of those won't be processed by 13 00:01:07,660 --> 00:01:13,030 specifying Exit 0 or Exit 1 or some other non-zero number. 14 00:01:13,060 --> 00:01:16,960 We said the exit status but enough talking. 15 00:01:17,060 --> 00:01:19,820 Let's write some script to see it in practice. 16 00:01:22,230 --> 00:01:25,590 We can check exit status is also here in termino. 17 00:01:25,860 --> 00:01:33,410 But first to make sure that our show is abash by typing ecord a lot assign 0. 18 00:01:33,780 --> 00:01:36,260 I can see that my show is back. 19 00:01:37,080 --> 00:01:41,680 I can easily change it to for example Desch by typing that. 20 00:01:42,090 --> 00:01:52,170 Because this is located in bin and bin is included in my pop. 21 00:01:52,390 --> 00:02:00,370 Now I can switch to for example s h which is by looking using ls command. 22 00:02:05,100 --> 00:02:08,550 Only the link to dash. 23 00:02:09,100 --> 00:02:23,170 I can switch back to bed now and can use Wopat been beshe or only in my case. 24 00:02:23,300 --> 00:02:27,960 So now let's write some commands and see data exit statuses right. 25 00:02:28,010 --> 00:02:33,180 Echo Hello body. 26 00:02:33,300 --> 00:02:35,920 And now to display the Is that right. 27 00:02:36,800 --> 00:02:38,250 The Larson questionmark 28 00:02:41,280 --> 00:02:43,080 you see that exit status is zero. 29 00:02:43,080 --> 00:02:45,360 That means that the command was successful. 30 00:02:45,360 --> 00:02:54,120 We can also try to do some variable assignment using what will that equals five multiply by 5 and we 31 00:02:54,120 --> 00:02:56,070 see that exit status is zero. 32 00:02:56,070 --> 00:03:00,020 Again let's make some error in our command. 33 00:03:00,150 --> 00:03:00,490 Right. 34 00:03:00,480 --> 00:03:04,230 Let the Vohra equals five a string. 35 00:03:04,860 --> 00:03:09,500 It is not possible to do multiplication with stink by typing Ecko dollar sign. 36 00:03:09,590 --> 00:03:10,400 Question mark. 37 00:03:10,410 --> 00:03:14,940 We see that as his status is one that means that something was wrong with that. 38 00:03:14,960 --> 00:03:15,870 C'mon. 39 00:03:16,890 --> 00:03:22,950 Maybe you think that working here in terminal is useless when we cannot type more comments on more lines 40 00:03:23,160 --> 00:03:27,140 because command on the line is executed immediately. 41 00:03:27,480 --> 00:03:28,680 But it's not true. 42 00:03:28,680 --> 00:03:30,960 We can write more commands here. 43 00:03:30,990 --> 00:03:38,340 I will show you how in our previous example we let I woke up and semicolon which means that I can write 44 00:03:38,430 --> 00:03:41,810 another command and both commands will be executed. 45 00:03:42,030 --> 00:03:46,830 So lots of printing of the result ecord called dollar sign. 46 00:03:46,850 --> 00:03:49,540 Vohra great. 47 00:03:49,920 --> 00:03:54,940 Have you noticed that when we displaying existences we've got only numbers. 48 00:03:55,050 --> 00:03:56,370 Let's make it more readable. 49 00:03:56,370 --> 00:04:04,990 So when we in future will ask for existing tools we will get exit's that those equals some number Varietes 50 00:04:05,010 --> 00:04:15,650 that was exposed dollar sign question mark semi-colon equal status equals dollar sign status. 51 00:04:15,660 --> 00:04:18,900 Now we see that previous command was successful. 52 00:04:18,990 --> 00:04:21,880 So I will again put them on with led operation 53 00:04:25,380 --> 00:04:30,450 and I can see that as that status is one great. 54 00:04:30,510 --> 00:04:31,500 Now let's. 55 00:04:31,620 --> 00:04:43,670 Finally some script let's clear the screen and create a file called X-1 don't ask age. 56 00:04:43,940 --> 00:04:45,370 Start with. 57 00:04:46,320 --> 00:04:47,030 Been beshe 58 00:04:49,920 --> 00:04:55,400 next grade variable var and assigned to either value 1. 59 00:04:55,470 --> 00:05:04,550 We can then increment it using God command and then we can display the value after incrementation eco 60 00:05:08,150 --> 00:05:13,980 water Dorsai in water. 61 00:05:14,410 --> 00:05:16,930 Now I will keep a block of commenced fi's 62 00:05:24,620 --> 00:05:25,670 and save descript 63 00:05:30,330 --> 00:05:32,030 after changing permission. 64 00:05:36,200 --> 00:05:36,860 I can get 65 00:05:41,230 --> 00:05:41,930 great. 66 00:05:41,940 --> 00:05:42,980 It is working. 67 00:05:43,230 --> 00:05:50,420 I can check for that tools and it's zero scribbles executed successfully. 68 00:05:52,110 --> 00:05:58,440 Now that's actually descript using Gaumont exit. 69 00:05:59,000 --> 00:06:03,840 I will type exit one after second book of my code 70 00:06:15,580 --> 00:06:17,260 Solas around it. 71 00:06:18,220 --> 00:06:23,130 I see that only do Eco commands are printed and Eco's that those is 72 00:06:25,930 --> 00:06:29,670 one great. 73 00:06:29,940 --> 00:06:33,930 I can now type exit before second echo command. 74 00:06:44,190 --> 00:06:53,810 And Viele exiting with stutterers for example 5 when we add on it we can only see one output. 75 00:06:53,990 --> 00:07:00,490 Great exit status is five. 76 00:07:00,610 --> 00:07:05,700 You should only use exit stuff to see in a range from 0 to 200 55. 77 00:07:05,920 --> 00:07:08,920 If you exit divid for example 256 78 00:07:11,630 --> 00:07:18,370 exists that also will be in the the ID 0 for 257 will be at the start of the RAM and so on 79 00:07:21,080 --> 00:07:24,080 save the script and the Damita to seed 80 00:07:29,270 --> 00:07:32,450 and exit status is zero. 81 00:07:32,490 --> 00:07:39,700 As I said in our example I used exit command just to show you how it is working. 82 00:07:40,060 --> 00:07:44,980 In the real world you would use them if for example some condition were true. 83 00:07:45,280 --> 00:07:48,380 And we will definitely show this in and under the lecturer's.