Learning PowerShell command names
Learning names of commands and parameters requires a significant time investment with most command-line interfaces. The issue is that there are few patterns. Memorization is the only way to learn the commands and parameters that you need to use on a regular basis.
When you work with a new command or parameter, you can't always use what you already know. You have to find and learn a new name. Traditionally, command-line interfaces start with a small set of tools and grow with incremental additions. It's easy to see why there's no standard structure. This seems logical for command names since each command is a separate tool. PowerShell has a better way to handle command names.
Learning command names in traditional shells
Most commands are built to manage elements of the operating system or applications, such as
services or processes. The commands have names that may or may not fit into a family. For example,
on Windows systems, you can use the
net start and
net stop commands to start and stop a
service. Sc.exe is another service control tool for Windows. That name does not fit into the
naming pattern for the net.exe service commands. For process management, Windows has the
tasklist.exe command to list processes and the taskkill.exe command to kill processes.
Also, these commands have irregular parameter specifications. You can't use the
net start command
to start a service on a remote computer. The sc.exe command can start a service on a remote
computer. But to specify the remote computer, you must prefix its name with a double backslash. To
start the spooler service on a remote computer named DC01, you type
sc.exe \\DC01 start spooler.
To list tasks running on DC01, you use the /S parameter and the computer name without
backslashes. For example,
tasklist /S DC01.
Prior to PowerShell v6,
sc was an alias for the
Set-Content cmdlet. To run the sc.exe
command, you must include the file extension.
Services and processes are examples of manageable elements on a computer that have well-defined life cycles. You may start or stop services and processes, or get a list of all currently running services or processes. Although there are important technical distinctions between them, the actions you perform on services and processes are conceptually the same. Furthermore, the choices we make to customize an action by specifying parameters may be conceptually similar as well.
PowerShell exploits these similarities to reduce the number of distinct names you need to know to understand and use cmdlets.
Cmdlets use verb-noun names to reduce command memorization
PowerShell uses a "verb-noun" naming system. Each cmdlet name consists of a standard verb hyphenated with a specific noun. PowerShell verbs are not always English verbs, but they express specific actions in PowerShell. Nouns are very much like nouns in any language. They describe specific types of objects that are important in system administration. It's easy to demonstrate how these two-part names reduce learning effort by looking at a few examples.
PowerShell has a recommended set of standard verbs. Nouns are less restricted, but always describe
what the verb acts upon. PowerShell has commands such as
For this example of two nouns and verbs, consistency does not simplify learning that much. Extend that list to a standardized set of 10 verbs and 10 nouns. Now you only have 20 words to understand. But those words can be combined to form 100 distinct command names.
It's easy to understand what a PowerShell command does by reading its name. The command to shut
down a computer is
Stop-Computer. The command to list all computers on a network is
Get-Computer. The command to get the system date is
You can list all commands that include a particular verb with the Verb parameter for
Get-Command. For example, to see all cmdlets that use the verb
PS> Get-Command -Verb Get CommandType Name Definition ----------- ---- ---------- Cmdlet Get-Acl Get-Acl [[-Path] <String>]... Cmdlet Get-Alias Get-Alias [[-Name] <String... Cmdlet Get-AuthenticodeSignature Get-AuthenticodeSignature [-... Cmdlet Get-ChildItem Get-ChildItem [[-Path] <Stri... ...
Use the Noun parameter to see a family of commands that affect the same type of object. For example, run following command to see the commands available for managing services:
PS> Get-Command -Noun Service CommandType Name Definition ----------- ---- ---------- Cmdlet Get-Service Get-Service [[-Name] <String... Cmdlet New-Service New-Service [-Name] <String>... Cmdlet Restart-Service Restart-Service [-Name] <Str... Cmdlet Resume-Service Resume-Service [-Name] <Stri... Cmdlet Set-Service Set-Service [-Name] <String>... Cmdlet Start-Service Start-Service [-Name] <Strin... Cmdlet Stop-Service Stop-Service [-Name] <String... Cmdlet Suspend-Service Suspend-Service [-Name] <Str... ...
Cmdlets use standard parameters
As noted earlier, commands used in traditional command-line interfaces don't always have consistent parameter names. Parameters are often single-character or abbreviated words that are easy to type but aren't easily understood by new users.
Unlike most other traditional command-line interfaces, PowerShell processes parameters directly, and it uses this direct access to the parameters along with developer guidance to standardize parameter names. This guidance encourages but does not guarantee that every cmdlet conforms to the standard.
PowerShell also standardizes the parameter separator. Parameter names always have a '-' prepended to them with a PowerShell command. Consider the following example:
Get-Command -Name Clear-Host
The parameter's name is Name, but it is typed as
-Name when used on the command line as a
Here are some of the general characteristics of the standard parameter names and usages.
The Help parameter (?)
When you specify the
-? parameter on any cmdlet, PowerShell displays help for the cmdlet.
The cmdlet is not executed.
PowerShell has several common parameters. These parameters are controlled by the PowerShell engine. Common parameters always behave the same way. The common parameters are WhatIf, Confirm, Verbose, Debug, Warn, ErrorAction, ErrorVariable, OutVariable, and OutBuffer.
Recommended parameter names
The PowerShell core cmdlets use standard names for similar parameters. The use of these standard names is not enforced, but there is explicit guidance to encourage standardization.
For example, the recommended name for a parameter that refers to a computer is ComputerName, rather than Server, Host, System, Node, or some other common alternative. Other important recommended parameter names are Force, Exclude, Include, PassThru, Path, and CaseSensitive.