1 00:00:03,310 --> 00:00:08,130 Let's say we want to archive or store a user's home directory just in case we need it. 2 00:00:08,200 --> 00:00:11,290 One way to do that would be with a Taar command. 3 00:00:11,290 --> 00:00:15,170 The tar command originally stood for tape archive. 4 00:00:15,310 --> 00:00:21,060 But you can also use it to archive files to any storage device not just tapes. 5 00:00:21,250 --> 00:00:27,260 So we'll use type against TAR shows that it's a file on file system which is executable here in the 6 00:00:27,260 --> 00:00:28,490 user bin directory. 7 00:00:28,550 --> 00:00:31,580 And let's look at the man page for this command. 8 00:00:31,670 --> 00:00:36,100 I'm just going to move down here a little bit and look at these examples here. 9 00:00:36,380 --> 00:00:40,640 So these three examples are the three main uses of the tar command. 10 00:00:40,790 --> 00:00:46,070 Here you can see how to create an archive how to view the contents of an archive and how to extract 11 00:00:46,130 --> 00:00:48,130 the contents of an archive. 12 00:00:48,140 --> 00:00:54,350 So the dashi option is used to create an archive the dash f option allows you to specify the file name 13 00:00:54,380 --> 00:00:55,850 of the archive file. 14 00:00:56,030 --> 00:00:59,970 The Dashti option is to list the contents of an archive. 15 00:01:00,080 --> 00:01:05,540 The dash via option is for verbose and the dash x option is for extract. 16 00:01:05,540 --> 00:01:10,770 So let's try these commands out by the way if you want to get details on those of course. 17 00:01:10,910 --> 00:01:14,300 They are listed here and all the options in the man page. 18 00:01:14,300 --> 00:01:18,440 First let me create a directory in some files in there so we have something to play with and something 19 00:01:18,440 --> 00:01:19,820 to create an archive with. 20 00:01:19,820 --> 00:01:29,690 So let's say we have some cat videos Let's do this cat videos Admiral cat bar 21 00:01:32,360 --> 00:01:35,420 Let's call this one Tarth Paul. 22 00:01:35,610 --> 00:01:41,810 When I ask can we come up with here and let's do Luke Clocker. 23 00:01:42,310 --> 00:01:43,650 What or two more here. 24 00:01:43,650 --> 00:01:46,110 Obi Wan cat novae 25 00:01:48,980 --> 00:01:50,560 about had me. 26 00:01:50,990 --> 00:01:53,370 I'm a kitty cat him before here. 27 00:01:53,540 --> 00:01:57,980 So if we look at our cat videos director here we have some empty files that were created with the touch 28 00:01:57,980 --> 00:01:59,170 command. 29 00:01:59,180 --> 00:02:08,580 Now let's go ahead and create an archive of these cat videos Ashesi to create after specify a file will 30 00:02:08,580 --> 00:02:13,540 say cat videos dot Teej are since that is the convention. 31 00:02:13,560 --> 00:02:17,880 You don't have to do this but this is a good practice and they will give it a path to archive. 32 00:02:17,880 --> 00:02:23,390 So we're just going to archive cat videos that directory and all of its contents. 33 00:02:23,800 --> 00:02:26,930 So if I do ls here we have cat videos dot Taar. 34 00:02:27,030 --> 00:02:28,620 So the archive was created. 35 00:02:28,620 --> 00:02:30,660 Now let's look at the contents of that archive. 36 00:02:30,670 --> 00:02:37,250 Will the tar Dashti to list the contents of the archive and we have to give it a f. a file which is 37 00:02:37,260 --> 00:02:38,280 cat videos. 38 00:02:38,340 --> 00:02:39,130 They are. 39 00:02:39,330 --> 00:02:43,310 So that shows us the contents within that tar file. 40 00:02:43,470 --> 00:02:48,310 If you wanted to see the files as they were being added to the archive you can use the verbose option. 41 00:02:48,420 --> 00:02:52,060 So let's go ahead and just delete this tar file here now and do this. 42 00:02:52,080 --> 00:02:58,320 See verbose and then do cat videos TR and the cat videos directory. 43 00:02:58,320 --> 00:03:03,210 By the way you can leave off or leave on the directory separator. 44 00:03:03,210 --> 00:03:04,120 Either one is fine. 45 00:03:04,110 --> 00:03:05,710 I'm just going to leave it on for this time. 46 00:03:05,940 --> 00:03:12,030 So this time instead of silently creating our tar file the dash option allowed us to see what was being 47 00:03:12,060 --> 00:03:14,780 added to our archive as it was happening. 48 00:03:14,790 --> 00:03:17,800 Let's go ahead and restore the files from this archive somewhere. 49 00:03:17,790 --> 00:03:23,490 Let's go ahead just create a restore directory change into that directory and then what we're going 50 00:03:23,490 --> 00:03:27,270 to do is do an x for extract and then we got to give it a file. 51 00:03:27,390 --> 00:03:33,900 And of course dot dot is a parent directory of where we were just at and then Ford slashes a directory 52 00:03:33,900 --> 00:03:38,540 separator and then cat videos dot TAR is the name of the file. 53 00:03:38,550 --> 00:03:43,680 So again here Dot Dot forward slash I'm not doing anything that's necessarily related to tar. 54 00:03:43,680 --> 00:03:51,270 This is just a Linux convention of relative pathing how to get to a file that's in the parent directory 55 00:03:51,270 --> 00:03:52,870 of your current directory. 56 00:03:53,040 --> 00:03:58,920 By the way I could have used the full path I could use home vagrant cat video star but I'm not going 57 00:03:58,920 --> 00:03:59,730 to do that. 58 00:04:00,120 --> 00:04:06,300 OK so we have a command here dash X for extract dash for the file that we're going to use as our archive 59 00:04:06,300 --> 00:04:11,550 file which is not for cat video store and going to hit enter. 60 00:04:11,550 --> 00:04:17,450 So now if we look in this new directory here we have the cat videos directory created. 61 00:04:17,540 --> 00:04:23,490 And if we list the files in that cat videos directory we get all those files that were inside that archive. 62 00:04:23,820 --> 00:04:26,150 I'm just going to go ahead and remove all this right here. 63 00:04:29,130 --> 00:04:34,500 So this time let's use the verbose option to see exactly what we're extracting and this is typically 64 00:04:34,500 --> 00:04:35,440 what I like to do. 65 00:04:39,100 --> 00:04:43,810 OK this shows that it's created the directory and then put those several files within that directory. 66 00:04:43,820 --> 00:04:48,520 OK I don't need that directory right now so I'm just going to delete it and I'm going to type CD dot 67 00:04:48,520 --> 00:04:52,960 dot to move back up to the parent directory and I'm back in my home directory. 68 00:04:53,170 --> 00:04:58,300 One of the common things people do with archive's is actually compress them to save some disk space. 69 00:04:58,300 --> 00:05:01,290 Now this can be a two step process like so. 70 00:05:01,390 --> 00:05:04,410 Let me go ahead just remove the tar file that was there. 71 00:05:04,630 --> 00:05:08,540 Let's create a cat video star file. 72 00:05:09,100 --> 00:05:15,780 And now let's zip it. 73 00:05:15,890 --> 00:05:21,950 By the way the JE's up command compresses the original file and appends a dot g the to the end of the 74 00:05:21,950 --> 00:05:22,740 file name. 75 00:05:22,760 --> 00:05:28,140 So if you see a file that ends in Tarar GZ It's a compressed archive. 76 00:05:28,310 --> 00:05:31,390 Now to decompress or uncompress a zip file. 77 00:05:31,400 --> 00:05:37,920 Use the unzip. 78 00:05:37,930 --> 00:05:40,810 Now we have our uncompressed original tar file back. 79 00:05:40,810 --> 00:05:43,270 Let's go ahead and delete that. 80 00:05:43,330 --> 00:05:46,490 You can perform the compression on the archive when you create it. 81 00:05:46,630 --> 00:05:49,250 If you use the dash the option to TAR. 82 00:05:49,270 --> 00:05:55,790 So what we can do here is to tar Dasch Z for compress and see we're going to create an archive. 83 00:05:55,980 --> 00:05:59,680 Is going to be verbose EFIS we're going to give a file name 84 00:06:03,000 --> 00:06:10,830 and then a path to what we're going to put in our archive here we can see we have our cat videos at 85 00:06:10,880 --> 00:06:12,890 Target gz file. 86 00:06:12,980 --> 00:06:17,830 And if we want to view the contents of a compressed archive we also need the dash CSY option. 87 00:06:17,840 --> 00:06:23,340 So we'll do our dash z t to list verbose Ephor file. 88 00:06:23,420 --> 00:06:24,360 You know the drill. 89 00:06:24,410 --> 00:06:29,090 We'll give it the path and then we can see the contents of that archive without actually extracting 90 00:06:29,090 --> 00:06:29,270 it. 91 00:06:29,270 --> 00:06:31,700 So let me go ahead and just delete that right now. 92 00:06:31,700 --> 00:06:37,910 Sometimes people like to use the File Extension of dot P GZ to represent a compressed archive so we 93 00:06:37,910 --> 00:06:48,090 can do this Taar the CVF cat videos Dot T G Z and then give it a path. 94 00:06:48,130 --> 00:06:55,590 So it's just something to keep in mind that target Z and Dot T G Z are really the same thing. 95 00:06:55,600 --> 00:06:59,930 Let's go ahead and restore this compressed archive we'll go into our restored directory here. 96 00:07:00,160 --> 00:07:02,420 And there's nothing in our folder. 97 00:07:02,560 --> 00:07:08,500 So let's use the dash z option cause we're working with a compressed file and then provide the path 98 00:07:08,500 --> 00:07:09,070 to that file. 99 00:07:09,070 --> 00:07:11,700 Actually this time I'm going to use the full path 100 00:07:15,390 --> 00:07:15,730 OK. 101 00:07:15,770 --> 00:07:22,950 It displays what was extracted and if we look sure enough we see the contents of that archive has been 102 00:07:22,950 --> 00:07:24,810 extracted on disk. 103 00:07:24,960 --> 00:07:27,560 I want to point out something that's kind of important here. 104 00:07:27,600 --> 00:07:34,480 The tar command really like most Linux commands treat you like a knowledgeable sane responsible adult. 105 00:07:34,590 --> 00:07:37,860 So it will happily override anything in its way. 106 00:07:37,860 --> 00:07:40,300 It assumes you know what the heck you're doing. 107 00:07:40,500 --> 00:07:44,800 So let's add some text to a file just to change it up a little bit. 108 00:07:44,820 --> 00:07:51,070 So let's just put some text in here and to our cat videos file of Darth paw. 109 00:07:51,450 --> 00:07:58,440 And if we kept the contents of that file we'll see it says what we piped into it by the way exclamation 110 00:07:58,440 --> 00:08:04,440 mark dollar sign takes the very last argument on the previous command line and places it on the current 111 00:08:04,500 --> 00:08:05,370 command. 112 00:08:05,370 --> 00:08:12,390 So again we're using what's called event designators in bash and you can see that exclamation mark dollar 113 00:08:12,390 --> 00:08:17,070 sign expanded to the last thing on our previous command line here. 114 00:08:17,070 --> 00:08:18,590 Cat videos Darth paw. 115 00:08:18,760 --> 00:08:24,540 And then it displays the entire command it's going to be executed and then it displays the result of 116 00:08:24,540 --> 00:08:25,110 that command. 117 00:08:25,110 --> 00:08:27,590 Just another quick tip for you there. 118 00:08:27,600 --> 00:08:29,120 Anyway back to the original point. 119 00:08:29,120 --> 00:08:32,330 Let's go ahead and extract this archive again. 120 00:08:34,980 --> 00:08:41,250 Execute the most recent command that starts with C which is cat and if we can't get videos for it unless 121 00:08:41,320 --> 00:08:43,820 Darth paw nothing is returned. 122 00:08:44,010 --> 00:08:51,030 And if we look at a long listing of that file it now has a file length of 0 and so nothing is in it 123 00:08:51,030 --> 00:08:54,120 which is the original file or the father was in the archive. 124 00:08:54,120 --> 00:08:56,630 So again Taar there just overwrote the file. 125 00:08:56,640 --> 00:09:01,280 It didn't ask for a confirmation or anything like that it didn't give you a warning. 126 00:09:01,380 --> 00:09:03,340 It just went ahead and over of the file. 127 00:09:03,480 --> 00:09:08,520 So be very careful when you're extracting archives and just be conscious of what you're doing. 128 00:09:08,520 --> 00:09:13,490 This also goes without saying but Taar relies on file permissions like any other command does. 129 00:09:13,590 --> 00:09:17,960 So if you try to create an archive of files that you don't have permissions to. 130 00:09:17,970 --> 00:09:19,980 Well that's just not going to work. 131 00:09:19,980 --> 00:09:25,140 Also if you try to extract the contents of an archive to somewhere where you don't have permissions 132 00:09:25,140 --> 00:09:27,560 to that's not going to work either. 133 00:09:27,690 --> 00:09:32,180 So if you want to be sure you have permissions you suit you or become the user first. 134 00:09:32,190 --> 00:09:38,160 For example let's say you want to backup the contents of the forward slash ETSI directory that contains 135 00:09:38,190 --> 00:09:43,140 pretty much all of your configuration files on the system you'll need root privileges to do that because 136 00:09:43,140 --> 00:09:47,930 there are some files in NC that a normal user just does not have access to. 137 00:09:47,940 --> 00:09:55,800 So let's get back to our home directory and do suruh tar dashes Z Moli velt the verbose option see Alf 138 00:09:56,130 --> 00:10:05,050 recreate the see the T GZ file and will archive the contents of forward slash ETSI here like I just 139 00:10:05,050 --> 00:10:11,000 said I didn't use the verbose option mainly because I wanted you to see this particular message. 140 00:10:11,040 --> 00:10:15,640 TAR says I'm removing the leading forward slash from member names. 141 00:10:15,810 --> 00:10:20,400 If we look at the contents of the archive we'll see that there is no leading slashy there so do this 142 00:10:20,400 --> 00:10:29,580 tar ZDF at c TDC so we can see the last file there at CNN RC is not forward slash and C forward slash 143 00:10:29,610 --> 00:10:30,480 nano RC. 144 00:10:30,510 --> 00:10:33,800 It's just ETSI word slash nano RC. 145 00:10:33,840 --> 00:10:39,420 This allows you to extract the contents of the archive into a different location without overriding 146 00:10:39,450 --> 00:10:41,190 all the existing files. 147 00:10:41,190 --> 00:10:47,670 So if it preserves the leading slash forward slash and C for slice or C if you try to extract this archive 148 00:10:47,910 --> 00:10:49,490 then it would overwrite that file. 149 00:10:49,560 --> 00:10:51,750 And that may be not what you want to do. 150 00:10:51,750 --> 00:10:56,700 For example maybe you want to extract this into a different subdirectory and then compare the contents 151 00:10:56,760 --> 00:11:02,040 of that archive or that backup to what is currently on disk instead of just blowing right over and over 152 00:11:02,040 --> 00:11:03,630 writing it right away. 153 00:11:03,900 --> 00:11:09,450 So more or less here tar is going to remove the absolute pathing indicated by the leading forward slash. 154 00:11:09,450 --> 00:11:13,380 And it's just going to leave you with a relative path within your archive. 155 00:11:13,680 --> 00:11:17,280 There is one more thing I'd like to talk about with the tar command. 156 00:11:17,280 --> 00:11:21,890 Now you may have seen people leave off the leading hyphen and do things like this. 157 00:11:22,040 --> 00:11:27,370 Tarzi see CVF cat videos. 158 00:11:27,650 --> 00:11:31,090 TDC and then give a path. 159 00:11:31,130 --> 00:11:35,420 So this is an older type of syntax that is still supported to this very day. 160 00:11:35,510 --> 00:11:41,360 So I just want you to be aware of it in some documentation you might actually see mention of quote old 161 00:11:41,360 --> 00:11:42,420 options unquote. 162 00:11:42,560 --> 00:11:44,940 Well this is what they're talking about. 163 00:11:45,140 --> 00:11:51,950 If you use this old option syntax all the options must be written together as a single clomped set without 164 00:11:51,950 --> 00:11:55,530 spaces separating them or dashes preceding them. 165 00:11:55,550 --> 00:12:01,460 Also the set of letters must be the first to appear on the command line after tart's cell and then some 166 00:12:01,460 --> 00:12:02,690 whitespace. 167 00:12:02,690 --> 00:12:05,600 Old options cannot appear anywhere else. 168 00:12:05,600 --> 00:12:09,770 They must immediately followed tar with some whitespace. 169 00:12:09,770 --> 00:12:14,910 The letter of an old option is exactly the same letter as the corresponding short option. 170 00:12:14,930 --> 00:12:21,740 For example the old option t is the same as the short option Dashti when options require an argument. 171 00:12:21,740 --> 00:12:25,010 Those arguments have to be presented in the same order. 172 00:12:25,010 --> 00:12:28,800 This can get pretty confusing if you use multiple options and have an argument. 173 00:12:28,850 --> 00:12:31,560 So instead of worrying about how to do it correctly. 174 00:12:31,610 --> 00:12:35,980 Honestly my advice is to simply use a hyphen before your options. 175 00:12:35,990 --> 00:12:41,660 That way you can do things like this tar space Desch F and then provide whatever option you want to 176 00:12:41,660 --> 00:12:48,950 you after that command and then all your other options they can be Dessie dash V and so on and here's 177 00:12:48,950 --> 00:12:49,780 a path. 178 00:12:49,930 --> 00:12:55,970 And we do this and sure enough we get our archive created if we wanted to do it with the quote old style 179 00:12:55,970 --> 00:12:58,350 syntax we'd have to do this tar. 180 00:12:58,490 --> 00:13:02,740 See V.F. cat videos tar and then the path. 181 00:13:02,960 --> 00:13:04,220 So that works. 182 00:13:04,220 --> 00:13:11,720 So he couldn't do something like this for example tar Affe cat videos and then do see in the out here 183 00:13:11,960 --> 00:13:18,110 because one is going to try to do is interpret C and V as files that are to be added to the archive 184 00:13:18,350 --> 00:13:19,930 and not as options. 185 00:13:19,940 --> 00:13:24,710 So again it gets kind of confusing when this old syntax will just really treat tar like any other command 186 00:13:24,800 --> 00:13:30,620 or using dashes if some old grumpy Unix guy with suspenders and a beard yells at you for doing this 187 00:13:30,620 --> 00:13:33,960 we'll just tell him that I told you to do it and put the blame on me.