Ezine 177 - PowerShell Things Guy Has Forgotten to Tell You
Ezine 177 - PowerShell Things Guy Has Forgotten to Tell You
♣
The lunatics have taken over the asylum!
Everyone has their favourites, and also everyone has their Achilles
heels. This week Guy is away and 'Barking' Eddie is going to tell you
about stuff that Guy has forgotten to mention
about PowerShell. Yes, I really do come from Barking, which is in
Essex, England.
PowerShell's Tab Completion
Save time typing out the full PowerShell command and use Tab Completion instead. The principle is that once you
have typed enough of a command to make it unique, press tab and PowerShell's
intelligence reads your mind and completes the command. Recently I
discovered that Tab Completion also works with -parameters; the extra twist
is that tab cycles through available options -handy.
Example:
At the PowerShell prompt type just these 6
characters get-ch and then press tab. You should see the
full command get-ChildItem. Next, view the parameters, once get-ChildItem appears type just the
minus sign -
then press tab. (No space after -)
-WhatIf and -Confirm
Because that rogue Guy so rarely issues disclaimers, you really should
get into the habit of appending -WhatIf to see if the script is going do what
you thought it would. This technique is especially important when you
use verbs such as 'Set', or 'Remove'. To digress, you could list such
verbs with:
get-command -verb delete (or -verb set).
Profiles and Add-PSSnapin
Once you feel confident with the basics of PowerShell, then it's worth
researching how to create a profile, because these
settings will enhance your PowerShell
working environment. One of the jobs for a well managed profile is to
add snapins, such as those supplied by QAD. In a nutshell, snapins add
cmdlets that third parties have cleverly crafted to make
PowerShell easier to use in areas such as Active Directory.
In other ways Profiles are like a 'Startup' folder, or the
Autoexec.bat that we old-timers used to have fun configuring. Your
PowerShell
profile will work, provided you focus on the singular word profile, never
create anything with the plural of this noun.
See detailed
instructions here
Calculating IP Address
ranges is a black art, which many network managers solve by creating custom
Excel spreadsheets. IPAT cracks this problem of allocating IP addresses
in networks in two ways:
For Mr Organized there is a nifty subnet
calculator, you enter the network address and the subnet mask, then IPAT
works out the usable addresses and their ranges.
For Mr Lazy IPAT
discovers and then displays the IP addresses of existing computers.
Download the Free IP Address Tracker
Creating Your Own Cmdlets for Use in
PowerShell
This is a fiddly technique, which could cause frustration for beginners. Long term it is best to store each set of PowerShell commands in a text files with .ps1 extension, these
scripts are called
cmdlets. The one piece of essential information that you need to know
before you can actually run these cmdlets, is that you have to adjust the
script ExecutionPolicy. My favoured way of doing that is to issue
PowerShell's own command: set-ExecutionPolicy remotesigned.
Check your setting with get-ExecutionPolicy. To be fair to Guy, he has
created a page on creating
cmdlets.
The reason for this one-off configuration change is security. By
default PowerShell protects the operating system from rogue scripts. To
digress, VBScript malware is so effective because all that the bad people
have to do is lure you to double click on a .vbs
and thus fire off a virus that they wrote. PowerShell takes security
seriously this is why you cannot
double-click a .ps1 file and expect it to execute. Instead the
technique is to create a store of .ps1 files then run them from the
PowerShell command line with ./file.ps1. Actually, it's not essential
to add the .ps1 extension when you run the cmdlet, dot slash filename is all
you need.
Remoting
The killer weakness of PowerShell v 1.0 is 'Remoting'. You have to
rely on WMI work-arounds to run scripts on another machine. People
always say that 'This feature will be fixed in the next version', in the
case of PowerShell v 2. it's true, you can see 'Remoting' in version 2 CTP
(Community Technical Preview). The only reason that Guy has been reticent
in extolling the benefits of PowerShell v 2.0 simply because you should NOT
use it in a production environment.
.Net Framework
Do nothing! Although PowerShell requires .Net Framework. You don't need to
study, or learn one thing about .Net to use PowerShell. Another
example of how PowerShell 'takes care of business'.
If you are looking for handy network utilities, try some of the free downloads at
Tools4Ever
If you like this page then please share it with your friends
See More Microsoft PowerShell WMI Examples:
• Home •
PowerShell Get-WmiObject •
PowerShell -Query •
PowerShell Select
• Win32_pingstatus •
WMI Win32_NetworkAdapter •
Win32_NetworkAdapterConfig
•
Disable NIC •
PowerShell -Filter •
Windows
PowerShell •
PowerShell 3.0 Network
Please email me if you have any example scripts. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.
Download my ebook:
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1) Getting Started
2) Real-life tasks
3) Examples of Syntax.
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