WEBVTT

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>> Hello, everyone. I'm
instructor Gerri Roberts,

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and this is
PowerShell Scripting.

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In this video,
we're going to talk

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about what a command is,

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and how commands are
structured in PowerShell.

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First of all, what is a command?

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Simply put, a command
is just a bunch of

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words or a single word that's

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been put together to do

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>> something such
as Get- EventLog,

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>> which would help you retrieve
an EventLog in Windows.

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In PowerShell, they
are also called

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cmdlets, or commandlets.

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There are pre-defined
cmdlets in PowerShell,

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and some that you can add.

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Packages of commands are
often called modules.

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There are modules for some
things that you can add.

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These could be for a
program or a specific task.

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For example, there are modules

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specifically made for Azure,

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and there are
actual modules made

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specifically for
scripting tasks.

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In PowerShell, there's usually

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a structure to the
command or the cmdlet.

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Here we have an example of

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a command that's trying
to get an EventLog,

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and specifically looking
for the one called

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Security on the
computer Gerri-PC2.

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At the end, we're
telling it that

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we want a lot of information.

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Verbose means that you're going

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to add a lot of
extra information.

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Now if we break
down this command,

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we can see that
at the beginning,

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the first item is a verb,

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the second item is a noun.

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Typically in PowerShell,

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commands are structured
with a verb, noun.

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This one's a Get-EventLog,

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and a lot of times you have

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commands that are
Get- something.

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You'll also have
commands that are Set-

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something or Add-
something a lot.

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Now the difference here is

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>> when you do a Get- something,

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>> you're usually just
pulling information.

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When you're doing
a Set- something,

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you're usually actually
setting a value

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such as a username or a
password for an account.

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If you're doing an
Add- something,

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you're usually adding
a new something

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like a new user or a new group.

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The next thing
you'll notice after

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our verb-noun structure
is a parameter.

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A parameter is an item where
we can put information in.

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Here, we have a parameter
for logged name.

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We're telling it that
we're looking for

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a specific log and then putting

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in a parameter value so it
knows which log to find.

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In this case, it's Security.

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Now we also have another
parameter here, computer name.

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Now we're telling it we're

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looking for the
LogName, Security,

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and then we're going
to look for it

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on this specific computer,

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and we pass the value Gerri-PC2.

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Now notice here that

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these parameters only
have a single value.

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Some parameters can
have multiple values,

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and those values typically
are separated by

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commas or quotation marks

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depending on the structure

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>> of that particular parameter.

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>> Now at the end, you
notice that you do

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have a switch parameter.

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Now, there are different
types of parameters.

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Here we see parameters
that take values,

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and such parameter
is a parameter

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that does not take your value,

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but does do something.

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Nouns and parameters are
normally in singular form.

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That just means commands and

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parameters will not usually
have an s at the end.

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Here's an example
we have Get-ADUser.

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When we put that command in and

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we put it in the dashes for

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the parameters and we put

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>> in those pieces
of information,

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>> we'll be able
to get information

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about an Active Directory user.

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However, if we added
an s at the end,

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and we did Get-ADUsers,

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we're going to get a
big old nice block of

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red text that's
an error and it's

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>> not going to be happy.

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>> Make sure when you're
typing it out this command,

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that you look and
see is this one

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that has an s because
those are very rare.

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Sometimes those are things like

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Get-process or Get-services
or things like

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that from the computer

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where the name of
the item already had

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an s. Most modules

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also have information on
where they come from.

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In the example above,

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when you look at that cmdlet,

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you see the AD for
Active Directory.

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Another thing you'll notice when

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you're putting in commands,

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if it's from a specific module,

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you're probably going
to have some sort of

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information in it to tell
you where it's coming from,

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such as our Active
Directory example.

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Now spacing, case-sensitive,
and other considerations.

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Watch your spacing, seriously.

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Improperly spaced commands
just are not going to run,

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you're going to
get a whole lot of

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red text and you're
not going to be happy.

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PowerShell uses these
spaces to know when

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to look for the next
item in the list.

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It will continue until it is

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lost if there is
not proper spacing.

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What will happen is the
command will run and

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then if hits where it's
not proper spacing,

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it's going to go, oops, I
don't know what that is.

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Here's a bunch of errors telling

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you that I don't
know what that is.

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Another thing with
PowerShell, case-sensitive.

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Some modules in PowerShell are

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case-sensitive, some are not.

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Quite a few of them.

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If you were to write
that Get-ADUser we

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saw earlier all in
lowercase would still work.

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But the important
part to remember is

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things that are values
like file paths,

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file names, folder paths,

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all that should be properly

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capitalized to avoid
confusion because it's

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not going to find what you
need or do what you need

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if it doesn't know
the proper value.

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If you're just not
sure if a module

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requires proper capitalization,
just do it anyways.

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It's not going to hurt to do

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capitalization when you
don't need to necessarily.

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The other thing,
use proper symbols.

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For example, don't
accidentally put

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an underscore in a command
that requires a dash,

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and put your slashes in
the correct direction.

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File paths or anything like
that that requires a slash,

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if the slash is in
the wrong direction,

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it's not going to find it,

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it's not going to do it,

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you're going to have a bad day.

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Make sure you put your

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>> slashes in the
correct direction.

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>> Post assessment
question time.

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What is a parameter
called that has

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no values being
passed through it?

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If you remember back
a couple slides,

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we talked about that.

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Is that a zero parameter,

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is that a switch parameter,

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is that a blank parameter,

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or a parameter null?

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You can pause for a moment
to figure out your answers.

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Our answer here is B,
a switch parameter.

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A switch parameter
has no value being

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passed through it and will
only have one effect.

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For example, in our
example earlier, verbose.

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Verbose is put there to add

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additional information about
the output of the item.