mattypenny

I’ve started knocking up a function to return the last few lines of a sqlserver errorlog.

This is a little way from being finished….but I’ve already found it quite handy

function get-sqlerrorlog { 

  [CmdletBinding()]	
  Param( 
      [String] [alias("computer")] $ComputerName,
      [Int] [alias("lines")] $NumberOfLines = 5
  )

  write-verbose "Running function $([string]$MyInvocation.MyCommand.name)"
  
  Write-verbose "`$ErrorLogFolder: $ErrorLogFolder"

  $ErrorLogFolder = dir sqlserver:\sql\$ComputerName 

  # Todo: need to work out how it works more > 1 named instance. This just picks 1st
  [string]$ErrorLogFolder = $($ErrorLogFolder | select -first 1).errorlogpath
  Write-verbose "`$ErrorLogFolder: $ErrorLogFolder"

  $ErrorLogFolder = $ErrorLogFolder.replace(':', '$')
  Write-verbose "`$ErrorLogFolder: $ErrorLogFolder"

  $ErrorLogFolder = '\\' + $ComputerName + '\' + $ErrorLogFolder
  Write-verbose "`$ErrorLogFolder: $ErrorLogFolder"

  # Todo: it might be that the get-content could be speeded up by retrieving less lines
  # Todo: seperate this bit out into seperate function ?  
  get-content "$ErrorLogFolder\ERRORLOG" | select -last $NumberOfLines                                                                
 
}
set-alias gsel get-sqlerrorlog

This is fairly trivial…and I’ve no idea if ‘aliasee’ is a real word or not, but I found this quite useful today:

get-alias | select ResolvedCommand, name | sort -property resolvedcommand

On my laptop, this gives:

ResolvedCommand                Name
---------------                ----
Add-Content                    ac
Add-PSSnapin                   asnp
Clear-Content                  clc
Clear-History                  clhy
Clear-Host                     cls
Clear-Host                     clear
Clear-Item                     cli
Clear-ItemProperty             clp
Clear-Variable                 clv
Compare-Object                 diff
Compare-Object                 compare
Connect-PSSession              cnsn
Convert-Path                   cvpa
Copy-Item                      cp
Copy-Item                      copy
Copy-Item                      cpi
Copy-ItemProperty              cpp
Disable-PSBreakpoint           dbp
Disconnect-PSSession           dnsn
Enable-PSBreakpoint            ebp
Enter-PSSession                etsn
Exit-PSSession                 exsn
Export-Alias                   epal
Export-Csv                     epcsv
Export-PSSession               epsn
ForEach-Object                 foreach
ForEach-Object                 %
Format-Custom                  fc
Format-List                    fl
Format-Table                   ft
Format-Wide                    fw
Get-Alias                      gal
get-cal                        cal
Get-ChildItem                  dir
Get-ChildItem                  ls
Get-ChildItem                  gci
Get-Command                    gcm
Get-Content                    cat
Get-Content                    gc
Get-Content                    type
get-functions                  getf
Get-History                    history
Get-History                    ghy
Get-History                    h
Get-Item                       gi
Get-ItemProperty               gp
Get-Job                        gjb
Get-Location                   pwd
Get-Location                   gl
Get-Member                     gm
Get-Module                     gmo
get-os                         gos
Get-Process                    gps
Get-Process                    ps
Get-PSBreakpoint               gbp
Get-PSCallStack                gcs
Get-PSDrive                    gdr
Get-PSSession                  gsn
Get-PSSnapin                   gsnp
Get-Service                    gsv
Get-Unique                     gu
Get-Variable                   gv
Get-WmiObject                  gwmi
Group-Object                   group
help                           man
Import-Alias                   ipal
Import-Csv                     ipcsv
Import-Module                  ipmo
Import-PSSession               ipsn
Invoke-Command                 icm
Invoke-Expression              iex
Invoke-History                 r
Invoke-History                 ihy
Invoke-Item                    ii
Invoke-Locate.ps1              locate
Invoke-NullCoalescing          ??
Invoke-RestMethod              irm
Invoke-WebRequest              wget
Invoke-WebRequest              iwr
Invoke-WebRequest              curl
Invoke-WmiMethod               iwmi
Measure-Object                 measure
mkdir                          md
Move-Item                      move
Move-Item                      mv
Move-Item                      mi
Move-ItemProperty              mp
New-Alias                      nal
New-Item                       ni
New-Module                     nmo
New-PSDrive                    mount
New-PSDrive                    ndr
New-PSSession                  nsn
New-PSSessionConfigurationFile npssc
New-Variable                   nv
Out-GridView                   ogv
Out-Host                       oh
Out-Printer                    lp
Pop-Location                   popd
powershell_ise.exe             ise
Push-Location                  pushd
Receive-Job                    rcjb
Receive-PSSession              rcsn
Remove-Item                    rmdir
Remove-Item                    del
Remove-Item                    rd
Remove-Item                    rm
Remove-Item                    erase
Remove-Item                    ri
Remove-ItemProperty            rp
Remove-Job                     rjb
Remove-Module                  rmo
Remove-PSBreakpoint            rbp
Remove-PSDrive                 rdr
Remove-PSSession               rsn
Remove-PSSnapin                rsnp
Remove-Variable                rv
Remove-WmiObject               rwmi
Rename-Item                    rni
Rename-Item                    ren
Rename-ItemProperty            rnp
Resolve-Path                   rvpa
Resume-Job                     rujb
Select-Object                  select
Select-String                  sls
Set-Alias                      sal
Set-Content                    sc
set-debug                      db
Set-Item                       si
Set-ItemProperty               sp
Set-Location                   sl
Set-Location                   chdir
Set-Location                   cd
Set-PSBreakpoint               sbp
Set-Variable                   sv
Set-Variable                   set
Set-WmiInstance                swmi
Sort-Object                    sort
Start-Job                      sajb
Start-Process                  start
Start-Process                  saps
Start-Service                  sasv
Start-Sleep                    sleep
Stop-Job                       spjb
Stop-Process                   kill
Stop-Process                   spps
Stop-Service                   spsv
Suspend-Job                    sujb
Tee-Object                     tee
Trace-Command                  trcm
Update-LocateDB.ps1            updatedb
Wait-Job                       wjb
Where-Object                   where
Where-Object                   ?
Write-Output                   write
Write-Output                   echo

For reasons that aren’t necessarily relevant, I wanted to use Remote Desktop to visit a list of servers¹. I tried doing this:

foreach ($S in "server01", "server02, "server03") { 
    mstsc /f /V:$S
}

This works….but it immediately starts rdp sessions to each of the servers. This is fine in this example, where there are only 3 servers, but in real life I’ve got a list of twenty or so and I don’t really want to open 20-odd rdp sessions at once.

What I did instead to force it do the rdp’s sequentially was this:

foreach ($S in "server01", "server02, "server03") { 
    mstsc /f /V:$S
    $ThrowAway = read-host "Hit Return"
}

This was the Powershell code I used to create the all the podcasts I’ve ever tweeted about post.

I downloaded the tweets from Twitter itself - I think there was a link somewhere within ‘Settings’

The .csv file looks like this:

So the code is:

$PodTweets = Import-Csv c:temptweets.csv | ? text -like "*podcast*"

$TweetsAsHtml = foreach ($P in $PodTweets)
{
#   write-output $P.timestamp.Substring(0,10)

   # Splitting the tweet text into words to allow for the processing of urls
   $TweetTextAsArray = $P.text.split(" ")

   $TextWithLink=""

   foreach ($Word in $TweetTextAsArray)
   {
        if ($Word -like "http:*")
        {
            # if there is an expanded_url, then use that instead
            if ($P.expanded_urls -ne "")
            {
                $Word = $P.expanded_urls

                # for some reason the expanded url is sometimes repeated in the download
                if ($Word -like "*,*")
                {
                    $Word = $Word.split(",")[0]
                }
            }

            # re-format the URL as a link
            $Word = "`<a href=`"$Word`"`>$Word`<`/a`>"
        }
        $TextWithLink = "$TextWithLink$Word "


    }

    # create an object and output that
    $properties = @{'TweetDate'=$P.timestamp.Substring(0,10);
                    'TweetText'=$TextWithLink}

    $ReformattedTweets = New-Object -Type PSObject -Prop $properties

    write-output $ReformattedTweets

}

$TweetsAsHtml | fl | out-file -encoding ascii -FilePath x.txt -width 1000

I hadn’t noticed this before.

If you do a dir listing of the databases for an instance within the Powershell Sqlserver provider, it doesn’t show the system databases

PS C:powershell> dir SQLSERVER:\SQL\my_pcinst2012\databases

Name                 Status          Recovery Model CompatLvl Collation                      Owner
----                 ------          -------------- --------- ---------                      -----
AdventureWorks2012   Normal          Simple               110 SQL_Latin1_General_CP1_CI_AS   matty
TSQL2012             Normal          Full                 110 Latin1_General_CI_AS           matty

To get a listing for the system databases you can do the following. I would imagine there’s a better way (perhaps some equivalent to ls -a?)…but I can’t think of it at the minute¹

PS C:powershell> foreach ($DB in ("master", "msdb", "model", "tempdb")) {gi SQLSERVER:\SQL\my_pcinst2012\databases\$DB }

Name                 Status          Recovery Model CompatLvl Collation                      Owner
----                 ------          -------------- --------- ---------                      -----
master               Normal          Simple               110 Latin1_General_CI_AS           sa
msdb                 Normal          Simple               110 Latin1_General_CI_AS           sa
model                Normal          Simple               110 Latin1_General_CI_AS           sa
tempdb               Normal          Simple               110 Latin1_General_CI_AS           sa

---

1. The ‘better way’ is to use gci -force. That includes all the system databases. ↩︎

I’ve been playing with pattern matching in Powershell.

I was trying to use ‘-match’ to ‘Check if the string is a hexadecimal number’ for the ‘Perl one-liners in Powershell’ page I’ve been working on.

I can’t pretend to entirely understand or explain pattern matching in Powershell, or in linux, but this seems to work.

$X = "21e" ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}"

This says match the string against ‘any combination of the characters within the square brackets (i.e. the hex digits) to the same length as the original string’.

So, the square brackets contain the allowable characters.

The curly brackets give the number of characters.

I tried just doing:

$X = "21e" ; $X -match "[0123456789abcde]{$X.length}"

…but this didn’t seem to work.

Tests

I tried the following strings - they all seemed to come up with the right answer: ``` $ $X = "21e" ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}" True $ $X = "21edjhsd" ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}" False $ $X = "21e34782348237847832748723" ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}" True $ $X = "21e34782348237847832748723f" ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}" False $ $X = "21e34782348237847832748723acbdaaa" ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}" True $ $X = " " ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}" False ```

….although I’m not sure whether this is right or wrong:

$ $X = "" ; $Y = $X.length ; $X -match "[0123456789abcde]{$Y}"
True