Select a string from a tailing log - powershell

I have an application log for which I am trying to write a batch file that will tail the log and return strings that contain "queue size" so that the updating queue size can be displayed. Basically the Windows equivalent of:
tail -f app.log | grep "queue size"
From what I've read I would need to use Windows powershell. I have devised the following script:
powershell -command Select-String -Path C:\logs\app.log -Pattern "queue size"
This gives me the following error:
Select-String : A positional parameter cannot be found that accepts
argument 'size'. At line:1 char:1
+ Select-String -Path C:\logs\app.log -Pattern queue size
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [Select-String], ParameterBindingException
+ FullyQualifiedErrorId : PositionalParameterNotFound,Microsoft.PowerShell.Commands.SelectStringCommand
Although this as it stands doesn't work, would it constantly update with the current logic?

No, the PowerShell command will not continue to read the log as it's being updated. PowerShell can't really handle this task, so you'd be better off grabbing a Windows port of the Unix tail command (e.g. from GnuWin32 or UnxUtils) and use it with the batch find command:
tail -f C:\path\to\app.log | find "queue size"

You need to wrap the command in double quotes and use single quotes for the pattern:
powershell -command "Select-String -Path C:\logs\app.log -Pattern 'queue size'"

this should do:
cat c:\path\to\app.log -tail 100 -wait | select-string "queue size"
cat is an alias for Get-Content...
The -wait parameter will make it wait for log updates.

Related

I am unable to change the extension of a multiple files using the powershell

To change the extension of files located at: C:\Users\mohit singh\Desktop\spotlight, I typed the following command in the PowerShell
C:\Users\mohit singh\Desktop\spotlight> ren *.* *.jpg
But I get the following error:
ren : Cannot process argument because the value of argument "path" is not valid. Change the value of the "path"
argument and run the operation again.
At line:1 char:1
+ ren *.* *.jpg
+ ~~~~~~~~~~~~~
+ CategoryInfo : InvalidArgument: (:) [Rename-Item], PSArgumentException
+ FullyQualifiedErrorId : Argument,Microsoft.PowerShell.Commands.RenameItemCommand
You're trying to use the ren command from within PowerShell. However, ren in Powershell is an alias to Rename-Item which is a different command. Powershell and cmd are different shells that use different command interpreters.
Your simplest option is just to run your command from a cmd window, instead of Powershell.
But if you wanted to use Powershell, you can do this by getting every file in the current folder, piping it to Rename-Item, then using the ChangeExtension .Net API to change its extension (which is safer than simple string replacement).
Get-ChildItem -File | Rename-Item -NewName { [io.path]::ChangeExtension($_.Name, "jpg") }
If you want to act on subfolders too, add -Recurse to Get-ChildItem.

Literal quotes in "Powershell Start-Process -ArgumentList"

I am currently attempting to create a command that opens an admin Powershell from the right click context menu. For context, context menu commands run in CMD.
My issue is that I am trying to cd into the directory where the right click occurs. The below command works just fine for most directories, but if the directory path contains a space, then it will only try to move into the portion of the path before the space, throwing an error. My understanding is that the current directory is passed in through %V but when I run the command echo %V using the same process, it splits paths with a space onto 2 lines, so I assume the parts of the path are stored in separate strings?
Powershell -noexit "Start-Process 'C:\Users\<me>\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Windows PowerShell\Windows PowerShell.lnk' -ArgumentList '-noexit','Set-Location -literalPath `"%V`"' -Verb RunAs"
I have updated the above command to match a suggestion below, and when right clicking on the desktop (which previously worked due to a lack of spaces) I now get the following error:
Set-Location : Cannot find path 'C:\Users\<me>\Desktop`' because it does not exist.
At line:1 char:1
+ Set-Location -literalPath `C:\Users\<me>\Desktop`
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (C:\Users\<me>\Desktop`:String) [Set-Location], ItemNotFoundException
+ FullyQualifiedErrorId : PathNotFound,Microsoft.PowerShell.Commands.SetLocationCommand
Note that in both of the above code blocks, <me> is my actual username.
I've been tearing my hair out trying to put quotes around the path but I can't seem to get Powershell to put the quotes in due to the fact that I already use both single and double quotes.
Any help would be greatly appreciated, thanks in advance.
Edit:
For those still looking for an answer, I ran the following Powershell script to add functional commands to my context menu:
$menu = 'Open Windows PowerShell Here as Administrator'
$command = "$PSHOME\powershell.exe -NoExit -NoProfile -Command ""Set-Location '%V'"""
'directory', 'directory\background', 'drive' | ForEach-Object {
New-Item -Path "Registry::HKEY_CLASSES_ROOT\$_\shell" -Name runas\command -Force |
Set-ItemProperty -Name '(default)' -Value $command -PassThru |
Set-ItemProperty -Path {$_.PSParentPath} -Name '(default)' -Value $menu -PassThru |
Set-ItemProperty -Name HasLUAShield -Value ''
}
The answer was found from How do I start PowerShell from Windows Explorer?
If you want to avoid space issues, you can reuse " by escaping it with ` in a string.
For example :
$command = "Set-Location `"C:\temp\test space`""
String will become this and spaces will be handled correctly :
Set-Location "C:\temp\test space"

Powershell parameter $args[0] with quotes

I'm running a PowerShell script invoked from a batch that pass a filename as first parameter.
Inside the script I use:
$file = Get-Item -LiteralPath $args[0]
But when the filenames contains a quote (I.E: my'file.txt) the get-item triggers an error. I've tried to remove the -LiteralPath parameter but the problem is the same.
The syntax of the script is
$file = Get-Item -LiteralPath $args[0]
write-host $file
cmd /c pause
If I run the script against my'file.txt I get:
C:\m\tag\testscript.ps1 'C:\m\tag\my'file.txt' <<<<
CategoryInfo : ParserError: (:String) [], ParentContainsErrorRecordException
FullyQualifiedErrorId : TerminatorExpectedAtEndOfString
Supposing you are passing the path in this way in your file batch:
powershell.exe C:\path\myscript.ps1 "%1%"
you need to escape the quote:
powershell.exe C:\path\myscript.ps1 \"%1%\"
How are you passing the parameter?
This works:
.{gi -literalpath $args[0]} "my'file.txt"
I think that maybe by the time PowerShell sees the filename cmd has stripped off any surround double quotes so PowerShell sees the lone single quote as a parse error. Try specifying the filename like so
my''file.txt

Powershell variables in command not working

I've tried a ton of different variations of this, but I can't get it to work. I am trying to run mysqldump to export a database (in this case called global).
PS C:\Users\Administrator> &"$mysqlpath\mysqldump.exe -u$mysqluser -p$mysqlpass --databases global | Out-File $env:TEMP\database_backup\global_$timestamp.sql -Encoding UTF8"
& : The term 'C:\Program Files\MySQL\MySQL Server 5.6\bin\mysqldump.exe -ubackup -pbackup_password --databases global | Out-File C:\Users\ADMINI~1\AppData\Local\Temp\2\database_backup\global_2013-12-11T11:47:28.sql -Encoding UTF8' is
not recognized as the name of a cmdlet, function, script file, or operable program. Check the spelling of the name, or
if a path was included, verify that the path is correct and try again.
At line:1 char:2
+ &"$mysqlpath\mysqldump.exe -u$mysqluser -p$mysqlpass --databases global | Out-Fi ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (C:\Program File... -Encoding UTF8:String) [], CommandNotFoundException
+ FullyQualifiedErrorId : CommandNotFoundException
It looks like it is being exploded into the proper variable names, but I can't get it to run.
UPDATE: So that was the right answer, I had a : in the timestamp. My other problem was solved by putting the variables inside double quotes (")
You are telling Powershell to run an EXE named
&"$mysqlpath\mysqldump.exe -u$mysqluser -p$mysqlpass --databases global | Out-File $env:TEMP\database_backup\global_$timestamp.sql -Encoding UTF8"
So remove the quotes (") and try again. Like so,
& $mysqlpath\mysqldump.exe -u$mysqluser -p$mysqlpass --databases global | Out-File $env:TEMP\database_backup\global_$timestamp.sql -Encoding UTF8

Trying to copy a group of files contained in a text file

I'm trying to copy a list of files from a txt file and as a newbie, I'm having a hard time.
Here is a bit of the text file. The real file has no extra lines, but I had to do that to :
"D:\Shared\Customer Care\Customer Care Common\Customers Contracted\Customers Contracted\Fred 44705"
"D:\Shared\Customer Care\Customer Care Common\Customers Contracted\Customers Contracted\Johnson 47227"
"D:\Shared\Customer Care\Customer Care Common\Customers Contracted\Customers Contracted\Daniel 35434"
"D:\Shared\Customer Care\Customer Care Common\Customers Contracted\Customers Contracted\Frank, John 48273"
I've tried enclosing the filename string in double-quotes as well.
Here's the simple script I'm trying to use:
Get-Content c:\users\scripts\files-to-fix.txt | Foreach-Object {copy-item $_ d:\junk}
The error I'm getting is:
Copy-Item : Cannot find drive. A drive with the name ''D' does not
exist. At C:\users\mhyman\scripts\copyfiles.ps1:2 char:81
+ Get-Content c:\users\mhyman\scripts\files-to-fix.txt |
Foreach-Object {copy-item <<<< $_ d:\junk}
+ CategoryInfo : ObjectNotFound: ('D:String) [Copy-Item],
DriveNotFoundException
+ FullyQualifiedErrorId :
DriveNotFound,Microsoft.PowerShell.Commands.CopyItemCommand
I know this is simple, but I would really appreciate some help.
I think it is the surrounding quotes that are causing the problem ( as indicated by the error saying that a drive of name "D is not found. Try this:
get-content c:\users\scripts\files-to-fix.txt | %{ copy-item $_.trim('"') d:\junk}
Of course, if you can control the txt file, enter the list without the quotes.
By your tags and drive letters and backslashes it is clearly a Windows environment your working in and although I'm not a PowerShell scripter, I'm a better than most batch scipter and use a For / If conditioanla statement sicne it is shorter and you feed it your file instead of parsing out the file into reduudc commands on a line, so in your example:
for /F %%t in (the text file.txt) do copy /q %%t d:\junk
And then you go home and never worry about until the next morning
Does powershell have a runas ornative mode that can parse older, more proven and stable DOS commands ?