1 00:00:02,940 --> 00:00:05,550 So enough of me chatting about all of this. 2 00:00:05,550 --> 00:00:07,570 Let's go back into PowerShell one more time, 3 00:00:07,570 --> 00:00:11,310 and let me give you a demonstration of working with some common string, 4 00:00:11,310 --> 00:00:12,930 date, and number techniques, 5 00:00:12,930 --> 00:00:16,010 and I also want to try to pull a lot of material from this course 6 00:00:16,010 --> 00:00:19,600 all together in some more practical examples. 7 00:00:19,600 --> 00:00:24,340 Let's first look at working with numbers in PowerShell. 8 00:00:24,340 --> 00:00:26,520 PowerShell includes some built‑in shortcuts, 9 00:00:26,520 --> 00:00:29,210 some of these you have seen already in the course, 10 00:00:29,210 --> 00:00:31,640 but let me go over them again. 11 00:00:31,640 --> 00:00:33,930 You can do, for example, one KB. 12 00:00:33,930 --> 00:00:36,830 If you don't remember how many bytes are in 1 KB, 13 00:00:36,830 --> 00:00:41,090 these numeric shortcuts will give you a value in bytes. 14 00:00:41,090 --> 00:00:44,400 So instead of having to type or try to figure out what's 3 KB, 15 00:00:44,400 --> 00:00:54,740 I can just do 3 KB, or 1 MB, or 1 GB, or even 1 TB. 16 00:00:54,740 --> 00:00:55,500 You can do math. 17 00:00:55,500 --> 00:00:59,020 I can say take this number, which I may have gotten from a process, 18 00:00:59,020 --> 00:01:03,940 or a file size, or from somewhere, say, what is this value in megabytes? 19 00:01:03,940 --> 00:01:04,570 And there we go. 20 00:01:04,570 --> 00:01:08,990 Using the megabytes shortcut, I can convert that value of bytes, 21 00:01:08,990 --> 00:01:14,040 assuming it's bytes, into a value of megabytes. 22 00:01:14,040 --> 00:01:18,390 You can also use the as operator, which we looked at all so early in the course, 23 00:01:18,390 --> 00:01:22,210 and say, hey, take this value, I'm going to divide by 1 GB, 24 00:01:22,210 --> 00:01:26,240 and treat it as an integer, which has the effect of rounding it, 25 00:01:26,240 --> 00:01:31,680 so there we go, so that would be then 51 GB. 26 00:01:31,680 --> 00:01:35,720 Now, PowerShell doesn't have any cmdlets to do math, 27 00:01:35,720 --> 00:01:38,880 but there is a .NET class that you can use, 28 00:01:38,880 --> 00:01:42,400 and you can access the methods of that class in 29 00:01:42,400 --> 00:01:45,620 order to do mathematical operations. 30 00:01:45,620 --> 00:01:48,320 This is a little different because we are going to access 31 00:01:48,320 --> 00:01:51,540 the .NET Framework directly in PowerShell, 32 00:01:51,540 --> 00:01:54,150 and we're going to access the math class, 33 00:01:54,150 --> 00:01:56,940 which we're going to put in square brackets. 34 00:01:56,940 --> 00:02:00,640 Now, this math class has a bunch of methods. 35 00:02:00,640 --> 00:02:02,140 A lot of these methods are repeated. 36 00:02:02,140 --> 00:02:03,040 There are different ways to use these, 37 00:02:03,040 --> 00:02:05,920 so I'm going to group them on the Name property. 38 00:02:05,920 --> 00:02:08,680 Here then is a list of all of the methods, 39 00:02:08,680 --> 00:02:09,870 and on the right side, 40 00:02:09,870 --> 00:02:12,620 you can see some of the different ways that you can 41 00:02:12,620 --> 00:02:14,860 use these particular methods. 42 00:02:14,860 --> 00:02:15,750 I'm going to show you some of them. 43 00:02:15,750 --> 00:02:19,140 We're not going to get into all of them. 44 00:02:19,140 --> 00:02:22,180 So let's look at, for example, the power method. 45 00:02:22,180 --> 00:02:25,370 Some of these methods will have multiple ways that they can be used, 46 00:02:25,370 --> 00:02:28,180 so I'm using the OverloadedDefinitions property on 47 00:02:28,180 --> 00:02:30,880 the method in order to get this. 48 00:02:30,880 --> 00:02:32,210 This tells me, 49 00:02:32,210 --> 00:02:37,180 and this is the same information that you would see in the GetMember output. 50 00:02:37,180 --> 00:02:41,460 This shows me that this method will write a double type of object, 51 00:02:41,460 --> 00:02:46,940 which is just another type of number with a decimal point in it. 52 00:02:46,940 --> 00:02:51,520 So I'm going to invoke the math operator, and that is the double colons here. 53 00:02:51,520 --> 00:02:57,390 That is the invoking a static method, so I'm going to raise 2 to the third power, 54 00:02:57,390 --> 00:02:59,420 and of course, that gives me 8. 55 00:02:59,420 --> 00:03:03,400 Now, if I need to find out, say, the square root of 144, 56 00:03:03,400 --> 00:03:07,440 and obviously, I can see that it is 12. 57 00:03:07,440 --> 00:03:13,540 Now, one method that I think you will use a lot is the round method. 58 00:03:13,540 --> 00:03:16,430 You see there are lots of ways to use this. 59 00:03:16,430 --> 00:03:17,200 Primarily, 60 00:03:17,200 --> 00:03:21,450 the way that I use it is I specify the value and then 61 00:03:21,450 --> 00:03:23,000 the number of decimals that I want. 62 00:03:23,000 --> 00:03:25,340 Here, let me show you. 63 00:03:25,340 --> 00:03:28,130 So if I take a number, we'll save it to variable $i, 64 00:03:28,130 --> 00:03:34,440 and I want to round that to 2 decimal places. 65 00:03:34,440 --> 00:03:35,170 There we go. 66 00:03:35,170 --> 00:03:36,570 It's really that easy. 67 00:03:36,570 --> 00:03:38,670 And this rounding still gives me a number. 68 00:03:38,670 --> 00:03:42,630 So if I were to do this with a group of objects and wanted a sort on its value, 69 00:03:42,630 --> 00:03:46,080 it will sort properly because it is a number. 70 00:03:46,080 --> 00:03:50,040 So let's use some of these techniques in PowerShell. 71 00:03:50,040 --> 00:03:53,000 Let me do Get‑ChildItem on my scripts folder and get 72 00:03:53,000 --> 00:03:58,840 all of the files that are ps*, and I'm going to measure them, 73 00:03:58,840 --> 00:04:01,060 and I'm going to measure the Length property and get the sum, 74 00:04:01,060 --> 00:04:04,540 and I'm going to save this result to $m. 75 00:04:04,540 --> 00:04:08,040 So if I look at the Sum property of the measurement object, 76 00:04:08,040 --> 00:04:10,180 so that is a value in bytes of all, basically, 77 00:04:10,180 --> 00:04:13,050 all of my PowerShell files in the scripts folder. 78 00:04:13,050 --> 00:04:14,100 I don't know about you, 79 00:04:14,100 --> 00:04:16,630 but I'm not necessarily very good at looking at that number going, 80 00:04:16,630 --> 00:04:19,590 oh, that's so and so kilobytes or megabytes. 81 00:04:19,590 --> 00:04:25,640 So I can divide that Sum by 1 KB or divide it by 1 MB. 82 00:04:25,640 --> 00:04:31,540 Okay, so I've got 13.3 MB worth of files. 83 00:04:31,540 --> 00:04:35,320 I could say, let's go back to the kilobyte version and treat it as an integer, 84 00:04:35,320 --> 00:04:40,640 so I'm rounding off those with decimal points. 85 00:04:40,640 --> 00:04:43,940 Let's use the round method here and format that sum value 86 00:04:43,940 --> 00:04:47,340 divided by 1 MB to 4 decimal places, 87 00:04:47,340 --> 00:04:51,340 and that gives me a result that might be more meaningful. 88 00:04:51,340 --> 00:04:53,340 Let's take this a step further. 89 00:04:53,340 --> 00:05:00,140 I am going to create a hash table called $get, 90 00:05:00,140 --> 00:05:04,300 and this hash table will be used to splat to Get‑ChildItem so all 91 00:05:04,300 --> 00:05:08,040 of the keys match parameters for Get‑ChildItem, 92 00:05:08,040 --> 00:05:10,160 and these are the values then that I will use. 93 00:05:10,160 --> 00:05:14,520 So I'm going to search the scripts folder for all files recursively, 94 00:05:14,520 --> 00:05:19,860 but exclude the list of files that you see there. 95 00:05:19,860 --> 00:05:28,140 And now I'm going to run Get‑ChildItem, splatting my hash table. 96 00:05:28,140 --> 00:05:34,040 Now because some of my files may not have extensions, 97 00:05:34,040 --> 00:05:37,140 I'm going to filter them with Where‑Object, 98 00:05:37,140 --> 00:05:43,740 I'm not using any operator here because if the object has an Extension property, 99 00:05:43,740 --> 00:05:48,240 if there's a value there, it will implicitly be true. 100 00:05:48,240 --> 00:05:53,210 So as long as whatever code in the script block for the Where‑Object is true, 101 00:05:53,210 --> 00:05:55,590 PowerShell will write that object to the pipeline, 102 00:05:55,590 --> 00:05:56,410 which is good. 103 00:05:56,410 --> 00:06:03,670 Because now I want to take those file objects and group them on the Extension, 104 00:06:03,670 --> 00:06:07,590 and I'm going to use a parameter here for Group‑Object called AsHashTable. 105 00:06:07,590 --> 00:06:09,420 This is going to take the output of Group‑Object 106 00:06:09,420 --> 00:06:11,180 and actually create a hash table, 107 00:06:11,180 --> 00:06:14,940 not a group measurement object as we have used in the past. 108 00:06:14,940 --> 00:06:16,370 And just to see what's going on here, 109 00:06:16,370 --> 00:06:20,240 I'm going to Tee the results to a Variable $g. 110 00:06:20,240 --> 00:06:23,820 So I'll be able to see the results as PowerShell does it, 111 00:06:23,820 --> 00:06:29,370 and I'm going to save the results to $g because I'm then going to use $g to 112 00:06:29,370 --> 00:06:34,640 do something else. So we'll give this a moment to finish. 113 00:06:34,640 --> 00:06:35,480 Alright, there we go. 114 00:06:35,480 --> 00:06:38,560 You can see all of the hash table. 115 00:06:38,560 --> 00:06:41,750 So there's the Name, which is the extension, and then the value 116 00:06:41,750 --> 00:06:45,840 are all the files that go with that extension. 117 00:06:45,840 --> 00:06:53,070 Now, let's take $g, and I'm going to use the GetEnumerator method 118 00:06:53,070 --> 00:06:56,140 that we looked at in the lesson on hash tables. 119 00:06:56,140 --> 00:07:02,240 I want to enumerate this hash table and select a few properties. 120 00:07:02,240 --> 00:07:04,770 So the Name property on the hash table, 121 00:07:04,770 --> 00:07:07,820 I'm just going to rename and call it file type. 122 00:07:07,820 --> 00:07:14,240 I'm using select object and using this hash table that we've seen before. 123 00:07:14,240 --> 00:07:18,920 The count property I'm going to create, and the value will be the 124 00:07:18,920 --> 00:07:22,340 count of the value property of the hash table. 125 00:07:22,340 --> 00:07:28,670 So $_ is the current object in the pipeline, which is the enumerated element 126 00:07:28,670 --> 00:07:34,600 from the hash table, value is an array of files, and I'm getting the count 127 00:07:34,600 --> 00:07:40,840 property. That value will be used and displayed as count. 128 00:07:40,840 --> 00:07:46,410 I'm then going to create another property called SizeKB, and here, I'm 129 00:07:46,410 --> 00:07:50,940 going to have a nested expression where I'm going to take the value, so 130 00:07:50,940 --> 00:07:57,090 this can be all the files, and I'm going to pipe them to measure objects 131 00:07:57,090 --> 00:08:00,740 and get the sum of the length properties. 132 00:08:00,740 --> 00:08:05,250 Then I can do math on that value, like we did earlier, and 133 00:08:05,250 --> 00:08:10,740 divide that by 1 KB to 2 decimal points, 134 00:08:10,740 --> 00:08:15,950 and then last, I'll sort the object on the SizeKB that I'm 135 00:08:15,950 --> 00:08:20,410 creating in descending order, and then I just want to see the 136 00:08:20,410 --> 00:08:23,040 first 10 objects that come through. 137 00:08:23,040 --> 00:08:28,030 So try to visualize what PowerShell is doing here, and there is the output 138 00:08:28,030 --> 00:08:31,690 then. I could take this output, I could save it to a file, 139 00:08:31,690 --> 00:08:34,880 I could export it to CSV, lots of things that I could do with it 140 00:08:34,880 --> 00:08:38,040 because I'm working with an object in the pipeline. 141 00:08:38,040 --> 00:08:41,500 PowerShell had no command that was going to give me this information, 142 00:08:41,500 --> 00:08:44,810 but I was able to create and get what I needed in 143 00:08:44,810 --> 00:08:48,140 order to meet some business need. 144 00:08:48,140 --> 00:08:51,910 Let's look at one more practical example here. I'm going to use 145 00:08:51,910 --> 00:08:56,120 Get‑CIMInstance and get the Win32_OperatingSystem class, and I'm also 146 00:08:56,120 --> 00:09:01,640 going to save the output to a variable, $os. 147 00:09:01,640 --> 00:09:03,600 Then I want to display just the Caption, 148 00:09:03,600 --> 00:09:08,340 the TotalVisibleMemorySize, and the free physical memory. 149 00:09:08,340 --> 00:09:11,040 All right, so there's the result that I get. 150 00:09:11,040 --> 00:09:14,430 Don't assume that all the values are always in bytes. 151 00:09:14,430 --> 00:09:14,660 So, 152 00:09:14,660 --> 00:09:18,330 the numbers you see there actually are in kilobytes, and the 153 00:09:18,330 --> 00:09:22,400 only reason I know that is because when I first started doing 154 00:09:22,400 --> 00:09:24,810 this years ago, my values were off. 155 00:09:24,810 --> 00:09:29,870 So then I looked up the Win32_OperatingSystem. If you go to Microsoft, 156 00:09:29,870 --> 00:09:33,680 look at the documentation, and it will tell you that these values are in 157 00:09:33,680 --> 00:09:37,220 kilobytes. Now that I know that they are in kilobytes, 158 00:09:37,220 --> 00:09:42,100 I can create more meaningful output, like this, and I'm just 159 00:09:42,100 --> 00:09:45,740 going to reuse my saved variable here. 160 00:09:45,740 --> 00:09:47,740 So I'm going to select the Caption, 161 00:09:47,740 --> 00:09:51,870 create a custom property called TotalMemGB, so it's going to be the total 162 00:09:51,870 --> 00:09:57,040 visible memory size divided by 1 MB because it's already in kilobytes, and 163 00:09:57,040 --> 00:10:02,070 I'm going to treat this as an integer, and I'll do the same thing with the 164 00:10:02,070 --> 00:10:07,080 memory. Although, this time, I'm going to round that free physical memory 165 00:10:07,080 --> 00:10:10,040 to 2 decimal points. 166 00:10:10,040 --> 00:10:17,440 Now I can see that this computer has 16 GB of memory and 14.67 of it is free. 167 00:10:17,440 --> 00:10:20,320 PowerShell didn't have the tools to give me the information I wanted, 168 00:10:20,320 --> 00:10:28,000 but I was able to tell PowerShell using its language, this is what I need, show it to me.