Iterate & Search for a string in child items - powershell

I am trying to build a PowerShell script that iterates through a list of files and searches and removes a match, not having much luck, here is my script
$path = "D:\Test\"
$filter = "*.txt"
$files = Get-ChildItem -path $path -filter $filter
foreach ($item in $files)
{
$search = Get-content -path $path$item
$search| select-string -pattern "T|"
}
At the moment the script is just returning the whole content of the file and not the select string.
Basically each file in the folder will have a trailer record at the end i.e. T|1410 I need to iterate through all the files and delete the last line, some of these files will be 200mb+ can someone guide me please.
I've edited my script and now I am using the following method.
$path = "D:\Test\"
$filter = "*.txt"
$files = Get-ChildItem -path $path -filter $filter
foreach ($item in $files)
{
$search = Get-content $path$item
($search)| ForEach-Object { $_ -replace 'T\|[0-9]*', '' } | Set-Content $path$item
}
I am using Powershell v.2
However, this is adding a new empty line to my end of file as well as leaving the replace empty, how can I avoid this as well as starting the search from the bottom

-pattern "T|"
That pattern matches a "T" or nothing. But there is nothing between every pair of characters in any string. To avoid the usual regular expression handling of | as an alternates separator, use a backslash to match a literal |:
-pattern "T\|"
Alternately, use Select-String's -SimpleMatch switch to stop the argument to -Pattern being treated as a regular expression.

As Richard mentioned, you have to escape the | character.
You could also use the regex::escape function for that:
[regex]::Escape("T|")

Aside from escaping the characters the other option you have available is the -SimpleMatch switch. From TechNet
Uses a simple match rather than a regular expression match. In a simple match, Select-String searches the input for the text in the Pattern parameter. It does not interpret the value of the Pattern parameter as a regular expression statement.
If you don't want to have to worry about escaping the characters and are not using regex this would be the way to go.
$search | select-string -pattern "T|" -SimpleMatch

Related

PowerShell: Replace string in all .txt files within directory

I am trying to replace every instance of a string within a directory. However my code is not replacing anything.
What I have so far:
Test Folder contains multiple files and folders containing content that I need to change.
The folders contain .txt documents, the .txt documents contain strings like this: Content reference="../../../PartOfPath/EN/EndofPath/Caution.txt" that i need to change into this: Content reference="../../../PartOfPath/FR/EndofPath/Caution.txt"
Before this question comes up, yes it has to be done this way, as there are other similar strings that I don't want to edit. So I cannot just replace all instances of EN with FR.
$DirectoryPath = "C:\TestFolder"
$Parts =#(
#{PartOne="/PartOfPath";PartTwo="EndofPath/Caution.txt"},
#{PartOne="/OtherPartOfPath";PartTwo="EndofPath/Note.txt"},
#{PartOne="/ThirdPartOfPath";PartTwo="OtherEndofPath/Warning.txt"}) | % { New-Object object | Add-Member -NotePropertyMembers $_ -PassThru }
Get-ChildItem $DirectoryPath | ForEach {
foreach($n in $Parts){
[string]$PartOne = $n.PartOne
[string]$PartTwo = $n.PartTwo
$ReplaceThis = "$PartOne/EN/$PartTwo"
$WithThis = "$PartOne/FR/$PartTwo"
(Get-Content $_) | ForEach {$_ -Replace $ReplaceThis, $WithThis} | Set-Content $_
}
}
The code will run and overwrite files, however no edits will have been made.
While troubleshooting I came across this potential cause:
This test worked:
$FilePath = "C:\TestFolder\Test.txt"
$ReplaceThis ="/PartOfPath/EN/Notes/Note.txt"
$WithThis = "/PartOfPath/FR/Notes/Note.txt"
(Get-Content -Path $FilePath) -replace $ReplaceThis, $WithThis | Set-Content $FilePath
But this test did not
$FilePath = "C:\TestFolder\Test.txt"
foreach($n in $Parts){
[string]$PartOne = $n.PartOne
[string]$PartTwo = $n.PartTwo
[string]$ReplaceThis = "$PartOne/EN/$PartTwo"
[string]$WithThis = "$PartOne/FR/$PartTwo"
(Get-Content -Path $FilePath) -replace $ReplaceThis, $WithThis | Set-Content $FilePath
}
If you can help me understand what is wrong here I would greatly appreciate it.
Thanks to #TessellatingHeckler 's comments I revised my code and found this solution:
$DirectoryPath = "C:\TestFolder"
$Parts =#(
#{PartOne="/PartOfPath";PartTwo="EndofPath/Caution.txt"},
#{PartOne="/OtherPartOfPath";PartTwo="EndofPath/Note.txt"},
#{PartOne="/ThirdPartOfPath";PartTwo="OtherEndofPath/Warning.txt"}) | % { New-Object object | Add-Member -NotePropertyMembers $_ -PassThru }
Get-ChildItem $LanguageFolderPath -Filter "*.txt" -Recurse | ForEach {
foreach($n in $Parts){
[string]$PartOne = $n.PartOne
[string]$PartTwo = $n.PartTwo
$ReplaceThis = "$PartOne/EN/$PartTwo"
$WithThis = "$PartOne/FR/$PartTwo"
(Get-Content $_) | ForEach {$_.Replace($ReplaceThis, $WithThis)} | Set-Content $_
}
}
There were two problems:
Replace was not working as I intended, so I had to use .replace instead
The original Get-ChildItem was not returning any values and had to be replaced with the above version.
PowerShell's -replace operator is regex-based and case-insensitive by default:
To perform literal replacements, \-escape metacharacters in the pattern or call [regex]::Escape().
By contrast, the [string] type's .Replace() method performs literal replacement and is case-sensitive, invariably in Windows PowerShell, by default in PowerShell (Core) 7+ (see this answer for more information).
Therefore:
As TessellatingHeckler points out, given that your search strings seem to contain no regex metacharacters (such as . or \) that would require escaping, there is no obvious reason why your original approach didn't work.
Given that you're looking for literal substring replacements, the [string] type's .Replace() is generally the simpler and faster option if case-SENSITIVITY is desired / acceptable (invariably so in Windows PowerShell; as noted, in PowerShell (Core) 7+, you have the option of making .Replace() case-insensitive too).
However, since you need to perform multiple replacements, a more concise, single-pass -replace solution is possible (though whether it actually performs better would have to be tested; if you need case-sensitivity, use -creplace in lieu of -replace):
$oldLang = 'EN'
$newLang = 'FR'
$regex = #(
"(?<prefix>/PartOfPath/)$oldLang(?<suffix>/EndofPath/Caution.txt)",
"(?<prefix>/OtherPartOfPath/)$oldLang(?<suffix>/EndofPath/Note.txt)",
"(?<prefix>/ThirdPartOfPath/)$oldLang(?<suffix>/OtherEndofPath/Warning.txt)"
) -join '|'
Get-ChildItem C:\TestFolder\Test.txt -Filter *.txt -Recurse | ForEach-Object {
($_ |Get-Content -Raw) -replace $regex, "`${prefix}$newLang`${suffix}" |
Set-Content -LiteralPath $_.FullName
}
See this regex101.com page for an explanation of the regex and the ability to experiment with it.
The expression used as the replacement operand, "`${prefix}$newLang`${suffix}", mixes PowerShell's up-front string interpolation ($newLang, which could also be written as ${newLang}) with placeholders referring to the named capture groups (e.g. (?<prefix>...)) in the regex, which only coincidentally use the same notation as PowerShell variables (though enclosing the name in {...} is required; also, here the $ chars. must be `-escaped to prevent PowerShell's string interpolation from interpreting them); see this answer for background information.
Note the use of -Raw with Get-Content, which reads a text file as a whole into memory, as a single, multi-line string. Given that you don't need line-by-line processing in this case, this greatly speeds up the processing of a given file.
As a general tip: you may need to use the -Encoding parameter with Set-Content to ensure the desired character encoding, given that PowerShell never preserves a file's original coding when reading it. By default, you'll get ANSI-encoded files in Windows PowerShell, and BOM-less UTF-8 files in PowerShell (Core) 7+.

Select-String successfully finds a string, replacing that found string with something else fails

uniquefile1.txt is a file that has no carriage returns (if it matters) and is very long. I am trying to match a variety of patterns.
The text file is not open when the program runs.
I visually have checked that the file has my pattern exactly as
written, when using Select-String it confirms that the pattern
exists.
When I go to replace, if I do Out-Host and search my
output in my ide it does not show that it has changed. It is not
replacing this string, and I do not know what I am doing wrong.
There are no errors of any kind when running my code.
I have tried:
$file = Get-Content C:\Uniqueline1
$file.Replace($variableforpattern1, $varForReplacement) | Set-Content Uniquefile1.txt
As well as the above except with the actual strings in place of the variables.
$file = Get-Content C:\uniquefile1.txt -Raw
$SEL = Select-String -Path "C:\uniquefile1.txt" -Pattern ">>>11^A"
if ($SEL = $true)
{
write "true"
}
else
{
write "not true"
}
$file -replace ">>>11^A", ">>>0111^A" | Set-Content "C:\uniquefile1.txt"
AdminOfThings was correct, please see their comment. This character ^ has special meaning in Regex and must be escaped.
-replace uses regex for the search pattern and therefore must have regex-special characters escaped if they are to be matched literally. The \ is used for escaping.
$file = Get-Content C:\uniquefile1.txt -Raw
$file -replace '>>>11\^A', '>>>0111^A' | Set-Content C:\uniquefile1.txt
Select-String without the -SimpleMatch switch uses regex as well. I don't know how that ever matched for you if the -replace operation failed.

How to take a list of partial file names and return a list of the full file names with PowerShell

I’m wondering how to take a list of partial document names and return a list of the full document names with PowerShell.
I have ton of documents to do this with. We have a naming scheme: HG-xx-xx-###
The full naming scheme for the actual files is: HG-xx-xx-###.x.x_File_Name
I have a lot of different lists of file names like so:
HG-SP-HG-001
HG-WI-BE-005
HG-GD-BB-043
I'm trying to have program return a list of the full file names like so:
HG-SP-HG-001.1.6_Example
HG-WI-BE-005.1.0_Example
HG-GD-BB-043.1.1_Example
I've included both methods I've tried. I give it a list or even just one partial file name and I get nothing back.
I've tried two different ways and I'm at the end of my programming and googling capabilities, any ideas?
$myPath = 'P:\'
$_DocList = READ-HOST "Enter list of document ID's"
$_DocList = $_DocList.Split(',').Split(' ')
#Here I'm not sure if I should do it like so:
$output =
ForEach($_Doc in $_DocList)
{
$find = gci $myPath -Recurse |where{$_.name -contains $($_Doc)}
Write-Host "$find"
}
$output | clip
#or like this:
$_DocList | ForEach-Object
{
gci -Path $myPath -Filter $_ -Recurse
$info = Get-ChildItem $_.FullName | Measure-Object
if ($info.Count -ne 0) {
Write-Output "$($_.Name)"
}
} | clip
Doug Maurer's helpful answer shows a solution based on a wildcard pattern based to the -Filter parameter.
Since this parameter only accepts a single pattern, the Get-ChildItem -Recurse call must be called multiple times, in a loop.
However, since you're using -Recurse, you can take advantage of the -Include parameter, which accepts multiple patterns, so you can get away with one Get-ChildItem call.
While for a single Get-ChildItem call -Filter performs better than -Include, a single Get-ChildItem -Include call with an array of pattern is likely to outperform multiple Get-ChildItem -Filter calls, especially with many patterns.
# Sample name prefixes to search for.
$namePrefixes = 'HG-SP-HG-001', 'HG-WI-BE-005', 'HG-GD-BB-043'
# Append '*' to all prefixes to form wildcard patterns: 'HG-SP-HG-001*', ...
$namePatterns = $namePrefixes -replace '$', '*'
# Combine Get-ChildItem -Recurse with -Include and all patterns.
# .Name returns the file name part of all matching files.
$names = (Get-ChildItem $myPath -File -Recurse -Include $namePatterns).Name
Maybe something like this?
$docList = #('HG-SP-HG-*','HG-WI-BE-*','HG-GD-BB-*')
foreach($item in $docList)
{
$check = Get-ChildItem -Filter $item P:\ -File
if($check)
{
$check
}
}
Maybe something like this?
$docList = #('HG-SP-HG','HG-WI-BE','HG-GD-BB')
$docList | Get-ChildItem -File -Filter $_ -Recurse | select Name
When using the filter with partial names you'll need to specify wildcard
$names = 'HG-SP-HG','HG-WI-BE','HG-GD-BB'
$names | Foreach-Object {
Get-ChildItem -File -Filter $_* -Recurse
}
And if you only want the full path back, simply select it.
$names = 'HG-SP-HG','HG-WI-BE','HG-GD-BB'
$names | Foreach-Object {
Get-ChildItem -File -Filter $_* -Recurse
} | Select-Object -ExpandProperty FullName
If you have an established pattern of what the files look like, why not regex it?
# Use these instead to specify a docID
#$docID = "005"
#pattern = "^HG(-\w{2}){2}-$docID"
$pattern = "^HG(-\w{2}){2}-\d{3}"
Get-ChildItem -Path "P:\" -Recurse | ?{$_ -match $pattern}
Granted, there may be more efficient ways to do this, but it should be quick enough for a few thousand files.
EDIT: This is the breakdown of the regex pattern's hieroglyphics.
^ Start at the beginning
HG literal characters "HG"
(-\w{2})
( start of a grouping
- literal "-" character (hyphen)
\w{2}
\w any word character
{2} exactly 2 times
) End of the grouping
{2} exactly 2 times
- literal "-" character (hyphen)
\d any digit 0 through 9
{3} Exactly 3 times

Replace a non-unique line of text under a unique line of text in a text file using powershell

I have the following txt file.
[AppRemover]
Enable=0
[CleanWipe]
Enable=0
[RerunSetup]
Enable=0
How do I change the Enable=0 to Enable=1 under [CleanWipe] only?
Below is how I plan on using the code with my file.
$Path = C:\temp\file.txt
$File = Get-Content -Path $Path
# Code to update file
$File | Out-File $Path
You can use -replace to update the value if it is 0.
$Path = C:\temp\file.txt
(Get-Content $Path -Raw) -replace "(?<text>\[CleanWipe\]\r?\nEnable=)0",'${text}1' |
Set-Content $Path
Using a module that parses INI files will be the best solution though. I'd recommend trying PsIni.
Explanation:
The -Raw switch reads the file contents as a single string. This makes it easier to work with newline characters.
-replace performs a regex match and then replace. Below is the regex match breakdown.
(?<text>) is a named capture group. Anything matched within that capture group can be recalled in the replace string as '${text}'.
\[CleanWipe\] is a literal match of [CleanWipe] while escaping the [] characters with \.
\r? is optional carriage return
\n is the newline character
Enable= is a literal match
0 is a literal match
The replace string is the capture group contents and 1 when a match exists. Technically, a capture group is not needed if you want to use a positive lookbehind instead. The positive lookbehind assertion is (?<=). That solution would look like the following:
$Path = C:\temp\file.txt
(Get-Content $Path -Raw) -replace "(?<=\[CleanWipe\]\r?\nEnable=)0",'1' |
Set-Content $Path
The problem with the -replace solutions as they written is they will update the file regardless of a change actually being made to the contents. You would need to add an extra comparison to prevent that. Other issues could be extra white space on any of these lines. You can account for that by adding \s* where you think those possibilities may exist.
Alternative With More Steps:
$file = Get-Content $Path
$TargetIndex = $file.IndexOf('[CleanWipe]') + 1
if ($file[$TargetIndex] -match 'Enable=0') {
$file[$TargetIndex] = 'Enable=1'
$file | Set-Content $Path
}
This solution will only update the file if it meets the match condition. It uses the array method IndexOf() to determine where [CleanWipe] is. Then assumes the line you want to change is in the next index.
IndexOf() is not the only way to find an index. The method requires that your line match the string exactly. You can use Select-String (case-insensitive by default) to return a line number. Since it will be a line number and not an index (indexes start at 0 while line numbers start at 1), it will invariably be the index number you want.
$file = Get-Content $Path
$TargetIndex = ($file | Select-String -Pattern '[CleanWipe]' -SimpleMatch).LineNumber
if ($file[$TargetIndex] -match 'Enable=0') {
$file[$TargetIndex] = 'Enable=1'
$file | Set-Content $Path
}

PowerShell - lowercase text between two characters

I have a lot of .txt files where I need to lowercase content in between two characters - after "%" and before ";".
The code below makes all content in the files lowercase and I need it to only do it in all instances between the two characters as mentioned.
$path=".\*.txt"
Get-ChildItem $path -Recurse | foreach{
(Get-Content $_.FullName).ToLower() | Out-File $_.FullName
}
Here an example using regex replace with a callback function to perform the lowercase:
$path=".\*.txt"
$callback = { param($match) $match.Groups[1].Value.ToLower() }
$rex = [regex]'(?<=%)(.*)(?=;)'
Get-ChildItem $path -Recurse | ForEach-Object {
$rex.Replace((Get-Content $_ -raw), $callback) | Out-File $_.FullName
}
Explanation:
The regex uses a positive lookbehind to find the position of % and a lookahead for the position of ; and caputes everything between in a group:
The caputred group gets passed to the callbackfunction which invokes ToLower() on it.