What is the correct way of determining if a file or folder is empty in powershell? I came across this post and tried the example that the second user gave, and it worked.
Now, I've been checking if a directory is empty by using the length property, like this:
(Get-ChildItem -Path "C:\Users\someUser\Downloads\" -Recurse).Length)
However, that only returns the number of bytes that the file/folder has. I tested the length property and found that if you were to have a blank text file/folder placed in the downloads then the length property wouldn't return the correct value.
Can you use the length property to correctly determine the number of files/folders that a directory has?
Try this, it will count the number of items:
Get-ChildItem -Path "C:\Users\someUser\Downloads\" -Recurse | Measure-Object
if you want to be sure a file or folder is empty you can use the following:
for a file:
If ((Get-Content C:\YouFile.txt) -eq $Null) {
"The file is empty"
}
if the file contains white space it wont return as null, so if you want to check even white space you can use the following:
If ([string]::IsNullOrWhiteSpace((Get-Content C:\YourFile.txt))) {
"The file is empty"
}
for a folder:
If ((Get-ChildItem -Force C:\SomeFolder) -eq $Null) {
"the Folder is empty"
}
The other way to handle this is just to use the base static method in System.Io.Directory -- Directory.EnumerationFileSystemInfos() and see how many objects, if any, are returned. Note that a FileSystemInfo can be either a directory or file, so it'll work in your case.
[system.io.directory]::EnumerateFileSystemEntries("C:\temp")
Related
I first create my array with a list of files in a directory (and subdirectories) using the Cmdlet Get-ChildItem, and store them in a variable
$PSVariable = (Get-ChildItem -Path "F:\SQL_Backups" -Recurse *.bak).FullName
I echo the variable ($PSVariable), this is my output (as desired):
F:\SQL_Backups\INTRAPORTAL\StoreDevelopment\StoreDevelopment_backup_2021_02_11_003002_3930170.bak
F:\SQL_Backups\INTRAPORTAL\StoreDevelopment\StoreDevelopment_backup_2021_02_12_003002_4780885.bak
F:\SQL_Backups\JDASQL\DEVMOD\DEVMOD_backup_2021_02_10_190002_5130923.bak
F:\SQL_Backups\JDASQL\DEVMOD\DEVMOD_backup_2021_02_11_190003_7621021.bak
Goal:
I need to remove the directory path from each array entries so it only contains the file name that will be stored in a temporary variable within a foreach loop:
StoreDevelopment_backup_2021_02_11_003002_3930170.bak
StoreDevelopment_backup_2021_02_12_003002_4780885.bak
DEVMOD_backup_2021_02_10_190002_5130923.bak
DEVMOD_backup_2021_02_11_190003_7621021.bak
Some will recommend simply using (.Name) in the Get-ChildItem command, but I need the array to have both the path and filename (FullName) as the array's contents are being used for other parts of the function. I'm a novice when it comes to regular expressions and I can't seem to get the results in the goal section. I've even tried using trim() methods, but no luck. Any recommendations would greatly be appreciated. Thank you.
Expanding on what #AdminOfThings recommended, you are making more work for yourself than you need. PowerShell is an object based scripting language, so to succeed you should use its full POWER.
The approach you're taking now is to take only one property from this useful object and then find you need to start slicing and dicing it in order to make it work.
There's an easier way. We love easy here, and the easy way to do this is to take the full object and then pick and chose its properties where it makes sense, like this:
$i = 0
#changed to remove the .FullName at then end
$PSVariable = (Get-ChildItem -Path "F:\SQL_Backups" -Recurse *.bak)
ForEach ($item in $psVariable){
$i++
Write-host "Processing [$($item.Name)], item number $i of $($psVariable.Count)"
Copy-item -Path $item.FullName -Destination C:\temp -WhatIf
}
It gives you meaningful output and then you have the full selection of properties to work with.
The one that makes the most sense to use is just .Name as you reference above. But then you still have .FullName, which includes the qualified path as well.
If you want to see the full selection of properties, try this:
$PsVariable[0] | Format-list *
Offered only as an inferior option to that of FoxDeploy's you can also use Split-Path to get the filename from a path
$PSVariable = (Get-ChildItem -Path "F:\SQL_Backups" -Recurse *.bak).FullName
$PSVariable | Split-Path -Leaf
We are copying a long list of files from their different directories into a single location (same server). Once there, I need to rename them.
I was able to move the files until I found out that there are duplicates in the list of file names to move (and rename). It would not allow me to copy the file multiple times into the same destination.
Here is the list of file names after the move:
"10.csv",
"11.csv",
"12.csv",
"13.csv",
"14.csv",
"15.csv",
"16.csv",
"17.csv",
"18.csv",
"19.csv",
"20.csv",
"Invoices_Export(16) - Copy.csv" (this one's name should be "Zebra.csv")
I wrote a couple of foreach loops, but it is not working exactly correctly.
The script moves the files just fine. It is the rename that is not working the way I want. The first file does not rename; the other files rename. However, they leave the moved file in place too.
This script requires a csv that has 3 columns:
Path of the file, including the file name (eg. c:\temp\smefile.txt)
Destination of the file, including the file name (eg. c:\temp\smefile.txt)
New name of the file. Just the name and extention.
# Variables
$Path = (import-csv C:\temp\Test-CSV.csv).Path
$Dest = (import-csv C:\temp\Test-CSV.csv).Destination
$NN = (import-csv C:\temp\Test-CSV.csv).NewName
#Script
foreach ($D in $Dest) {
$i -eq 0
Foreach ($P in $Path) {
Copy-Item $P -destination C:\Temp\TestDestination -force
}
rename-item -path "$D" -newname $NN[$i] -force
$i += 1
}
There were no error per se, just not the outcome that I expected.
Welcome to Stack Overflow!
There are a couple ways to approach the duplicate names situation:
Check if the file exists already in the destination with Test-Path. If it does, start a while loop that appends a number to the end of the name and check if that exists. Increment the number you append after each check with Test-Path. Keep looping until Test-Path comes back $false and then break out of the loop.
Write an error message and skip that row in the CSV.
I'm going to show a refactored version of your script with approach #2 above:
$csv = Import-Csv 'C:\temp\Test-CSV.csv'
foreach ($row in $csv)
{
$fullDestinationPath = Join-Path -Path $row.Destination -ChildPath $row.NewName
if (Test-Path $fullDestinationPath)
{
Write-Error ("The path '$fullDestinationPath' already exists. " +
"Skipping row for $($row.Path).")
continue
}
# You may also want to check if $row.Path exists before attempting to copy it
Copy-Item -Path $row.Path -Destination $fullDestinationPath
}
Now that your question is answered, here are some thoughts for improving your code:
Avoid using acronyms and abbreviations in identifiers (variable names, function names, etc.) when possible. Remember that code is written for humans and someone else has to be able to understand your code; make everything as obvious as possible. Someone else will have to read your code eventually, even if it's Future-You™!
Don't Repeat Yourself (called the "DRY" principle). As Lee_daily mentioned in the comments, you don't need to import the CSV file three times. Import it once into a variable and then use the variable to access the properties.
Try to be consistent. PowerShell is case-insensitive, but you should pick a style and stick to it (i.e. ForEach or foreach, Rename-Item or rename-item, etc.). I would recommend PascalCase as PowerShell cmdlets are all in PascalCase.
Wrap literal paths in single quotes (or double quotes if you need string interpolation). Paths can have spaces in them and without quotes, PowerShell interprets a space as you are passing another argument.
$i -eq 0 is not an assignment statement, it is a boolean expression. When you run $i -eq 0, PowerShell will return $true or $false because you are asking it if the value stored in $i is 0. To assign the value 0 to $i, you need to write it like this: $i = 0.
There's nothing wrong with $i += 1, but it could be shortened to $i++, if you want to.
When you can, try to check for common issues that may come up with your code. Always think about what can go wrong. "If I copy a file, what can go wrong? Does the source file or folder exist? Is the name pulled from the CSV a valid path name or does it contain characters that are invalid in a path (like :)?" This is called defensive programming and it will save you so so many headaches. As with anything in life, be careful not to go overboard. Only check for likely scenarios; rare edge-cases should just raise errors.
Write some decent logs so you can see what happened at runtime. PowerShell provides a pair of great cmdlets called Start-Transcript and Stop-Transcript. These cmdlets log all the output that was sent to the PowerShell console window, in addition to some system information like the version of PowerShell installed on the machine. Very handy!
I'm finishing a script in PowerShell and this is what I must do:
Find and retrieve all .txt files inside a folder
Read their contents (there is a number inside that must be less than 50)
If any of these files has a number greater than 50, change a flag which will allow me to send a crit message to a monitoring server.
The piece of code below is what I already have, but it's probably wrong because I haven't given any argument to Get-Content, it's probably something very simple, but I'm still getting used to PowerShell. Any suggestions? Thanks a lot.
Get-ChildItem -Path C:\temp_erase\PID -Directory -Filter *.txt |
ForEach-Object{
$warning_counter = Get-Content
if ($warning_counter -gt '50')
{
$crit_counter = 1
Write-Host "CRITICAL: Failed to kill service more than 50 times!"
}
}
but it's probably wrong because I haven't given any argument to Get-Content
Yes. That is the first issue. Have a look at Get-Help <command> and or docs like TechNet when you are lost. For the core cmdlets you will always see examples.
Second, Get-Content, returns string arrays (by default), so if you are doing a numerical comparison you need to treat the value as such.
Thirdly you have a line break between foreach-object cmdlet and its opening brace. That will land you a parsing problem and PS will prompt for the missing process block. So changing just those mentioned ....
Get-ChildItem -Path C:\temp_erase\PID -Directory -Filter *.txt | ForEach-Object{
[int]$warning_counter = Get-Content $_.FullName
if ($warning_counter -gt '50')
{
$crit_counter = 1
Write-Host "CRITICAL: Failed to kill service more than 50 times!"
}
}
One obvious thing missing from this is you do not show which file triggered the message. You should update your notification/output process. You also have no logic validating file contents. The could easily fail, either procedural or programically, on files with non numerical contents.
I have a powershell script that creates folders on our NAS for each student according to their student numbers. The names for the folders comes from a .csv file that I import from the server. This is what I have got:
Set-Location "C:\studentdata"
$StudFolders = import-csv \\servername\datafolder\studfolders.csv
ForEach ($StudFolders in $StudFolders) {
if(Test-Path -Path C:\Studentdata\$StudFolders) {
New-Item $StudFolders.Name -type directory
}else{
"Folders already created"
}
}
This script works great, if I run it only once. If I run it again, I get errors in the console window about the folders already existing. What I want to do is catch the errors with the IF part of the script, but I am not sure if I have the correct usage of the IF for powershell. This will help if I edit the .csv with more student number it will display without errors.
Can someone point me in the right direction?
EDIT:
This is what I have in the studfolders.csv
Name
2003040052
2003060213
2003060310
2003060467
Lets take a look at your logic:
you are using an if statement, which works if something returns true
you are using a test-path cmdlet which returns true if something exists
See the problem? you need to do it vice versa:
if (!(test-path ...)) { ... } # ! - is the operator to invert true to false
or you can switch if and else content, so when if executes it returns "Folders already created", and else creates folders
As a matter of coding style, I would avoid using the same variable name with different semantics, as in ($Studfolders in $Studfolders). Code like this is very hard to read a few months down the road. I generally use the singular for each object in the collection, as in ($Studfolder in $Studfolders). But if your style works for you, OK.
Previous answers have already pointed out that your logic is backwards. You need to reverse it.
Next, it doesn't look to me as though you are accessing the component of each item in the loop. When you do an Import-Csv, several things happen: The first record in the csv file is treated as a header, providing the names for the fields that follow. If there is indeed a header in your csv file, you need to reference it when you retrieve the first field from each item, even if it's the only field.
The result of an import-csv is an array of custom objects. Each custom object looks like a hashtable that contains key, value pairs. Something like this might work
Set-Location "C:\studentdata"
$StudFolders = import-csv \\servername\datafolder\studfolders.csv
ForEach ($StudFolder in $StudFolders) {
if(Test-Path -Path C:\Studentdata\$StudFolder.Name) {
"Folders already created"
}else{
New-Item $StudFolder.Name -type directory
}
}
I have presumed that the first record in the Csv file looks like this:
"Name"
That is why I referenced the field as $Studfolder.Name"
If this isn't the case, you are going to have to do something different.
Having tried everything with the script, I could not get it to catch the errors. I decided to ask my manager, and he came up with the following solution that works quite well and catches the errors.
import-csv '\\servername\datafolder\studfolders.csv'|ForEach-Object -process {
$path =$_.Name
$path='C:\Studentdata\'+$path
if (Test-Path -Path $path){
"Folder already created"
} else {
New-Item $path -type directory
}
}
Thanks to #Walter Mitty and #4c74356b41 for help try to find an answer.
I have a list of pdf file names which i have stored in a text file line by line as shown below.
322223491.pdf
322223492.pdf
322223493.pdf
the name of the text file is inclusions.txt.
I am passing this to a variable:
$inclusion = get-content .\inclusions.txt
Now i want to check and display if a folder (C:\users\xyz) contains files passed in $inclusions variable how do i do that?
PS C:\users\xyz> Get-childitem
command displays the following
Mode LastWritetime Name
The Name column is the property of interest to me where in i want to compare my inclusions list and if its found in the list then i want to display them in the Powershell terminal
PS C:\users\xyz> Get-childitem | Select-Object -Property Name
is as far as i have got my head around it i dont know how to proceed further to display the filtered data by comparing it with the $inclusions variable.
Furthermore i want to delete the files if they match the name in the inclusions text file. So that is the final Objective to traverse through all the files in the folder compare if the name is same as in the inclusions list and if yes then delete those particular files.
Any help would be appreciated.
Many thanks
Use Where-Object to filter on a condition:
Get-ChildItem |Where-Object { $inclusion -contains $_.Name }
If you are only interested in the file names themselves, use Select-Object -ExpandProperty to grab just the name of each file:
Get-ChildItem |Where-Object { $inclusion -contains $_.Name } |Select-Object -ExpandProperty Name
If you want to do something based on whether a certain folder contains one or more of the files in $inclusion, use an if statement:
$folderPath = "C:\users\xyz\folder\of\interest"
if(#(Get-ChildItem $folderPath |Where-Object {$inclusion -contains $_.Name}).Count -ge 1)
{
Write-Host "Folder $folderPath contains at least one of the inclusion files"
}