Why am i not able to use $_ inside of text as one can use other variables?
Get-ChildItem -Path $path -filter *.mp3 | foreach {
$count++;
write-host "File${count}=${_.Name}";
}
I know I can write it this way:
Get-ChildItem -Path $path -filter *.mp3 | foreach {
$count++;
write-host "File${count}=$($_.Name)";
}
When you write ${_.Name} you're actually asking for the variable named _.Name, not the Name property of the $_ variable.
PS > ${_.Name} = "test"
PS > Get-Variable _*
Name Value
---- -----
_.Name test
The reason $($_.Name) works is because $() means "process this first", so you can specify whatever you want inside. In this case you just specified a variable name and the property you wanted, but you could also make it more complex like:
PS > $a = 1
PS > "A's value is 1(true or false?): $(if($a -eq 1) { "This is TRUE!" } else { "This is FALSE!" })"
A's value is 1(true or false?): This is TRUE!
PS > $a = 2
PS > "A's value is 1(true or false?): $(if($a -eq 1) { "This is TRUE!" } else { "This is FALSE!" })"
A's value is 1(true or false?): This is FALSE!
Related
I'm fairly new to powershell.
I'm trying to compare data in a CSV File against random files in a specific folder.
I want to see if and what has changed and then log that in another column called "Changed".
Here's what I've done below, it seems to create a new column called 'Changed' but doesn't input the changes in it.
$Spreadsheet = 'C:\Powershell\CSV\inv.csv'
$SpreadSheetPath = "C:\Powershell\CSV"
Import-Csv $Spreadsheet -Delimiter "|" -Encoding Default | ForEach-Object -
{
$Path += $_.Path
$Filename += $_.Filename
$DateModified += $_.DateModified
$FileSize += $_.FileSize
$MD5Hash += $_.MD5Hash
}
{
$Msg1 = "Path changed"
$Msg2 = "File Name changed"
$Msg3 = "Date Modified changed"
$Msg4 = "File Size changed"
$Msg5 = "MD5 changed"
$Msg6 = "Files are the same"
$psdata = "D:\ps-test\data\*.*"
}
If (($Path -eq $psdata))
{
Import-Csv C:\Powershell\CSV\inv.csv |
Select-Object *,#{Name='Changed';Expression={$Msg6}} |
Export-Csv C:\Powershell\CSV\NewSpreadsheet4.csv
}
Else
{
Import-Csv C:\Powershell\CSV\inv.csv |
Select-Object *,#{Name='Changed';Expression={$Msg1}} |
Export-Csv C:\Powershell\CSV\NewSpreadsheet4.csv
}
Here is an example of what the CSV looks like:
Path Filename Date Modified File Size MD5 Hash
D:\ps-test\data adminmodeinfo.htm 03/11/2010 22:42 1079 BD1C9468D71FD33BB35716630C4EC6AC
E:\ps-test\data admintoolinfo.htm 03/11/2010 22:42 868 24B99B6316F0C49C23F27FEA6FF1C6AC
E:\ps-test\data admin_ban.bmp 03/11/2010 22:42 63480 C856F1F3C58962B456E749F2EA9C933A
E:\ps-test\data baseline.dat 03/20/2010 03:18:33 173818 F13183D88AABD1A725437802F8551A06
E:\ps-test\data blueRule.gif 03/11/2010 22:42 815 D1AEFE884935095DAB42DAFD072AA46F
E:\ps-test\data deffactory.dat 03/20/2010 03:18:33 706 862D4DFD2F49021BB7C145BDAFE62F6F
E:\ps-test\data dividerArt.jpg 03/11/2010 22:42 367 F7050C596C097C0B01A443058CD15E35
There are many issues with your code.I will try to highlight a few of the issues, link to documentation and point you in the right direction so that you can resolve your issues. A proper solution would require getting many more requirements, or writing code (off-topic for StackOverflow)
Change
| ForEach-Object -
{
to
| ForEach-Object {
In the Foreach-Object, you are concatenating values from each line because you are using +=.
On the first run, $Path contains D:\ps-test\data.
After the second run, it contains D:\ps-test\dataE:\ps-test\data.
At the end of your test data, it contains D:\ps-test\dataE:\ps-test\dataE:\ps-test\dataE:\ps-test\dataE:\ps-test\dataE:\ps-test\dataE:\ps-test\data
The messages are contained in a script block, but it does not look like this is intentional as this is never executed. So after the scriptblock, the variable $Msg1 has not been created; it's blank.
If (($Path -eq $psdata))
double brackets not required.
will always be false because the variable $psdata does not exist as it was stated inside a script block.
will always be false because you are attempting to equate the strings; your input does not literally contain "D:\ps-test\data\*.*". You probably want -like instead of -eq.
will always be inaccurate because even if the paths are compared, there is no check that the file actually exists on the system.
Useful links
Test-Path to check if file exists.
Get-FileHash to get MD5 hash and compare to file.
Get-ChildItem to get a list of directories/files in a directory.
Write-Output so that you can print variables and make sure they contain what you expect.
about_comparison_operators - -in and -contains will help you.
This is a suggestion to help you get started. It's not complete and not tested! Let me know if it works as expected and if you have any questions.
Import-Csv 'C:\Powershell\CSV\inv.csv' -Delimiter "|" -Encoding Default | foreach {
$Path += $_.Path
$Filename += $_.Filename
$DateModified += $_.DateModified
$FileSize += $_.FileSize
$MD5Hash += $_.MD5Hash
$file = [System.IO.FileInfo](Join-Path $Path $Filename)
if (-not $file.Exists) {
$message = "File does not exist"
}
elseif ($file.LastWriteTime -ne [DateTime]$DateModified) {
$message = "Dates differ"
}
elseif ($file.Length -ne [int]$FileSize) {
$message = "Sizes differ"
}
# and so on...
# (You cannot really compared a changed file name btw)
New-Object -Type PSObject -Prop #{
Path = $Path
Filename = $Filename
DateModified = $DateModified
FileSize = $FileSize
MD5Hash = $MD5Hash
Message = $message
}
} | Export-CSV 'C:\Powershell\CSV\NewSpreadsheet4.csv'
I have a program writing text outputs to STDOUT. I would like to filter and color these outputs. In PowerShell, I wrote a CmdLet, which parses text lines and emits them to the console and colors certain parts if needed. Example
In PowerShell I have such a function:
function Write-ColoredProgLine
{ [CmdletBinding()]
param(
[Parameter(ValueFromPipeline=$true)]
$InputObject,
[Parameter(Position=1)]
[switch]$SuppressWarnings = $false,
[Parameter(Position=2)]
[string]$Indent = ""
)
begin
{ $ErrorRecordFound = $false }
process
{ if (-not $InputObject)
{ Write-Host "Empty pipeline!" }
elseif ($InputObject -is [string])
{ if ($InputObject.StartsWith("vlib "))
{ Write-Host "${Indent}$InputObject" -ForegroundColor Gray } }
elseif ($InputObject.StartsWith("** Warning:") -and -not $SuppressWarnings)
{ Write-Host "${Indent}WARNING: " -NoNewline -ForegroundColor Yellow
Write-Host $InputObject.Substring(12)
}
elseif ($InputObject.StartsWith("** Error:") -and -not $SuppressWarnings)
{ $ErrorRecordFound += 1
Write-Host "${Indent}WARNING: " -NoNewline -ForegroundColor Yellow
Write-Host $InputObject.Substring(12)
}
}
else
{ Write-Host "Unsupported object in pipeline stream" }
}
end
{ $ErrorRecordFound }
}
Usage:
$expr = "prog.exe -flag -param foo"
$errors = Invoke-Expression $expr | Write-ColoredProgLine $false " "
How can I process such operations in Bash?
I need some kind of inner state in the filter script, so tools like GRC are not powerful enough.
Here is a POSIX compatible way to do that:
awk '
/vlib/ {
$0 = "\33[1;36m" $0 "\33[m"
}
/warning/ {
$0 = "\33[1;33m" $0 "\33[m"
}
1
'
Result:
It should be noted that you cannot use POSIX Sed for this. While it is
tempting, POSIX Sed has no way to create the escape sequences needed here, while
POSIX Awk does.
You could use sed in your pipeline. Maybe it's not the easiest tool but very powerful. You can do pretty much with a substitution command:
echo test | sed -e 's/es/ES/'
output:
tESt
this could be used also for removing some patterns by substitution with nothing:
sed -e 's/pattern//'
and adding prefixes/suffixes to your patterns (& is your match):
sed -e 's/pattern/PREFIX&SUFFIX/'
For coloring syntax check this link:
http://ascii-table.com/ansi-escape-sequences.php
But if you need keeping some inner state it will be easier to use awk
I normally find the answer to my problem by going through the site, but this time I have read every question yet still I am in despair and really need an experienced eye.
What I have is basically a structural health monitoring system. I measure strains and receive raw data. This raw data is processed by a MATLAB executable that I wrote myself and then uploaded to an ftp-server. We had a student that automated this with a PowerShell script which was working perfectly until I changed literally one small line in MATLAB and recompiled the code.
I do not understand much about PowerShell, so please be patient with me. The error I receive is you cannot call a method on a null-valued expression. This occurs when I try to replace a set of strings (just called xxx_xxx) with a date that exists as a variable in PowerShell. I can see xxx_xxx in the command window (see attached image), I can print out the date that I want to use as replacement, but somehow it does not work.
I cannot provide a working code snippet because you would need the DAQ to generate data, and as I said, I don't understand the language much. But below is the code. For easier reading, the line that I am receiving the error is the following:
$outData = $cmdOutput.Replace("xxx_xxx",$snaps[$i].Substring(6,4)+"-"+$snaps[$i].Substring(3,2)+"-"+$snaps[$i].Substring(0,2)+" "+$snaps[$i].Substring(11,8)+";")
If anyone could help me with this, I would be eternally grateful!
$retry=3
while(1){
#$dir = "C:\Users\Petar\Documents\Zoo\PetarData\INPUT DATA\New folder\"
$dir = "C:\Users\Yunus\Documents\Micron Optics\ENLIGHT\Data\" + $(get-date -f yyyy) + "\" + $(get-date -f MM) + "\"
#$outdir = "C:\Users\Petar\Documents\Zoo\PetarData\OUTPUT DATA\New folder\"
$archivedirin = "C:\Users\Yunus\Documents\Elefantenhaus\Archive\IN\"
$archivedirout = "C:\Users\Yunus\Documents\Elefantenhaus\Archive\OUT\"
$tempdir = "C:\Users\Yunus\Documents\Elefantenhaus\Archive\TEMP\"
$prefix = "EHZZ";
$filecount=(Get-ChildItem $dir).Count
$latest = Get-ChildItem -Path $dir | Sort-Object LastAccessTime -Descending | Select-Object -First 1
if($filecount -gt 1){
$exclude = $latest.name
$Files = GCI -path $dir | Where-object {$_.name -ne $exclude}
$dest = $archivedirin + "batch_"+$(get-date -f MM-dd-yyyy_HH_mm_ss)+"\"
new-item -type directory $dest
foreach ($file in $Files){move-item -path ($dir+$file) -destination $dest}
$latest = Get-ChildItem -Path $dest | Sort-Object LastAccessTime -Descending | Select-Object -First 1
$filename = $dest + $latest.name
$s=Get-Content $filename
while($s -eq $null){
if($retry -lt 0){break}
write-host "could not read file"
$retry = $retry -1
$s=Get-Content $filename
}
#read content of input file
$snaps = $s
#loop through the lines in the file until the first occurence of a timestamp, that is our desired line
for ($i = 0; $i -lt $snaps.length; $i++)
{
$ismatch =[regex]::Matches($snaps[$i], '^(\d\d.\d\d.\d\d\d\d\s\d\d+)')
if ( $ismatch -ne $null -and $ismatch[0].Groups[1].Value)
{
$temp=Get-Content $filename | select -skip $i
$filenametemp = $tempdir+"\temp.txt" #temp file path, don't change the filename "temp.txt"
#$filename3 = $tempdir+"\test.txt"
Add-Content $filenametemp $temp
$filename = $archivedirout+$prefix+"_"+$snaps[$i].Substring(8,2)+$snaps[$i].Substring(3,2)+$snaps[$i].Substring(0,2)+"_"+$snaps[$i].Substring(11,2)+$snaps[$i].Substring(14,2)+$snaps[$i].Substring(17,2)+".txt"
$cmdOutput = (cmd /c new_modified.exe $tempdir) | Out-String
write-output $cmdOutput #"$cmdOutput is:"
#IF ([string]::IsNullOrWhitespace($cmdOutput)){
# break
#}
$outData = $cmdOutput.Replace("xxx_xxx",$snaps[$i].Substring(6,4)+"-"+$snaps[$i].Substring(3,2)+"-"+$snaps[$i].Substring(0,2)+" "+$snaps[$i].Substring(11,8)+";")
Add-Content $filename $outData
remove-item -path $filenametemp
break
}
}
#break
}
else
{
write-host "waiting for file"
}
Start-Sleep -s 30
}
I think what is happening is that the output of the external program isn't being piped into a variable correctly. I haven't had a chance to test this but Tee-Object looks like the appropriate method for you.
I would suggest you try replacing...
$cmdOutput = (cmd /c new_modified.exe $tempdir) | Out-String
with...
cmd /c new_modified.exe $tempdir | Tee-Object -variable $cmdOutput
I have a list of files in a folder each are in this format: custID_invID_prodID or custID_invID_prodID_Boolvalue. For every file I need to break it into sections based on '_'. Currently I have this code:
$files = Get-ChildItem test *.txt
foreach($f in $files){
$file = #()
$file += ([String]$f).Split("_")
$total = ([String]$f).Split("_") | Measure-Object | select count
Write-Host "${total}"
if($total -eq 2) {
for($i = 2; $i -lt $file.length; $i+=3) {
$file[$i] = $file[$i].trimend(".txt")
Write-Host "${file}"
}
}
}
The problem is that Write-Host "${total}" equals #{Count=#} where # is real number of times "_" is found in file. How can I use $total inside my if statement to do different operations based upon the number of "_" found?
Would it not be simpler just to assign the parts you want directly to named variables rather than working with an array?
foreach($f in (Get-ChildItem test *.txt)) {
$custId, $invID, $prodID, $Boolvalue = $f.BaseName -split "_"
Write-Host $custId, $invID, $prodID, $Boolvalue
}
If the name only has 3 parts this will simply set $Boolvalue to an empty string.
Also note that you don't have to trim the extension off the last element after splitting, just use the BaseName property to get the name without extension.
You need to get the count-property value, like $total.count in your if test. You could also clean it up like this.
$files = Get-ChildItem test *.txt
foreach($f in $files){
$file = #(([String]$f).Split("_"))
Write-Host "$($file.Count)"
if($file.Count -eq 2) {
for($i = 2; $i -lt $file.length; $i+=3) {
$file[$i] = $file[$i].trimend(".txt")
Write-Host "${file}"
}
}
}
If you had included more information about what you were trying to do, we could clean it up alot more. Ex. It's seems like you want to do something like this:
Get-ChildItem test *.txt | ForEach-Object {
$file = #($_.BaseName.Split("_"))
Write-Host "$($file.Count)"
if($file.Count -eq 2) {
Write-Host $file
}
}
Seems to me that you're doing it the hard way. Why not:
$x = "aaa_bbb_ccc"
$cnt = $x.Split("_").count
I am currently working on editing one line of a text file. When I try to overwrite the text file, I only get one line back in the text file. I am trying to call the function with
modifyconfig "test" "100"
config.txt:
check=0
test=1
modifyConfig() function:
Function modifyConfig ([string]$key, [int]$value){
$path = "D:\RenameScript\config.txt"
((Get-Content $path) | ForEach-Object {
Write-Host $_
# If '=' is found, check key
if ($_.Contains("=")){
# If key matches, replace old value with new value and break out of loop
$pos = $_.IndexOf("=")
$checkKey = $_.Substring(0, $pos)
if ($checkKey -eq $key){
$oldValue = $_.Substring($pos+1)
Write-Host 'Key: ' $checkKey
Write-Host 'Old Value: ' $oldValue
$_.replace($oldValue,$value)
Write-Host "Result:" $_
}
} else {
# Do nothing
}
}) | Set-Content ($path)
}
The result I receive in my config.txt:
test=100
I am missing "check=0".
What have I missed?
$_.replace($oldValue,$value) in your innermost conditional replaces $oldValue with $value and then prints the modified string, but you don't have code printing non-matching strings. Because of that only the modified string are written back to $path.
Replace the line
# Do nothing
with
$_
and also add an else branch with a $_ to the inner conditional.
Or you could assign $_ to another variable and modify your code like this:
Foreach-Object {
$line = $_
if ($line -like "*=*") {
$arr = $line -split "=", 2
if ($arr[0].Trim() -eq $key) {
$arr[1] = $value
$line = $arr -join "="
}
}
$line
}
or a one liner.. (not exactly pin pointed answer, but to the question title)
(get-content $influxconf | foreach-object {$_ -replace "# auth-enabled = false" , "auth-enabled = true" }) | Set-Content $influxconf