build/dotSource/Replace-FileString.ps1
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function Script:Replace-FileString { <# .SYNOPSIS Replaces strings in files using a regular expression. .DESCRIPTION Replaces strings in files using a regular expression. Supports multi-line searching and replacing. .PARAMETER Pattern Specifies the regular expression pattern. .PARAMETER Replacement Specifies the regular expression replacement pattern. .PARAMETER Path Specifies the path to one or more files. Wildcards are permitted. Each file is read entirely into memory to support multi-line searching and replacing, so performance may be slow for large files. .PARAMETER LiteralPath Specifies the path to one or more files. The value of the this parameter is used exactly as it is typed. No characters are interpreted as wildcards. Each file is read entirely into memory to support multi-line searching and replacing, so performance may be slow for large files. .PARAMETER CaseSensitive Specifies case-sensitive matching. The default is to ignore case. .PARAMETER Multiline Changes the meaning of ^ and $ so they match at the beginning and end, respectively, of any line, and not just the beginning and end of the entire file. The default is that ^ and $, respectively, match the beginning and end of the entire file. .PARAMETER UnixText Causes $ to match only linefeed (\n) characters. By default, $ matches carriage return+linefeed (\r\n). (Windows-based text files usually use \r\n as line terminators, while Unix-based text files usually use only \n.) .PARAMETER Overwrite Overwrites a file by creating a temporary file containing all replacements and then replacing the original file with the temporary file. The default is to output but not overwrite. .PARAMETER Force Allows overwriting of read-only files. Note that this parameter cannot override security restrictions. .PARAMETER Encoding Specifies the encoding for the file when -Overwrite is used. Possible values are: ASCII, BigEndianUnicode, Unicode, UTF32, UTF7, or UTF8. The default value is ASCII. .INPUTS System.IO.FileInfo. .OUTPUTS System.String without the -Overwrite parameter, or nothing with the -Overwrite parameter. .LINK about_Regular_Expressions .EXAMPLE C:\>Replace-FileString.ps1 '(Ferb) and (Phineas)' '$2 and $1' Story.txt This command replaces the string 'Ferb and Phineas' with the string 'Phineas and Ferb' in the file Story.txt and outputs the file. Note that the pattern and replacement strings are enclosed in single quotes to prevent variable expansion. .EXAMPLE C:\>Replace-FileString.ps1 'Perry' 'Agent P' Ferb.txt -Overwrite This command replaces the string 'Perry' with the string 'Agent P' in the file Ferb.txt and overwrites the file. #> [CmdletBinding(DefaultParameterSetName="Path", SupportsShouldProcess=$TRUE)] param( [parameter(Mandatory=$TRUE,Position=0)] [String] $Pattern, [parameter(Mandatory=$TRUE,Position=1)] [String] [AllowEmptyString()] $Replacement, [parameter(Mandatory=$TRUE,ParameterSetName="Path", Position=2,ValueFromPipeline=$TRUE)] [String[]] $Path, [parameter(Mandatory=$TRUE,ParameterSetName="LiteralPath", Position=2)] [String[]] $LiteralPath, [Switch] $CaseSensitive, [Switch] $Multiline, [Switch] $UnixText, [Switch] $Overwrite, [Switch] $Force, [String] $Encoding="ASCII" ) begin { # Throw an error if $Encoding is not valid. $encodings = @("ASCII","BigEndianUnicode","Unicode","UTF32","UTF7", "UTF8") if ($encodings -notcontains $Encoding) { throw "Encoding must be one of the following: $encodings" } # Extended test-path: Check the parameter set name to see if we # should use -literalpath or not. function test-pathEx($path) { switch ($PSCmdlet.ParameterSetName) { "Path" { test-path $path } "LiteralPath" { test-path -literalpath $path } } } # Extended get-childitem: Check the parameter set name to see if we # should use -literalpath or not. function get-childitemEx($path) { switch ($PSCmdlet.ParameterSetName) { "Path" { get-childitem $path -force } "LiteralPath" { get-childitem -literalpath $path -force } } } # Outputs the full name of a temporary file in the specified path. function get-tempname($path) { do { $tempname = join-path $path ([IO.Path]::GetRandomFilename()) } while (test-path $tempname) $tempname } # Use '\r$' instead of '$' unless -UnixText specified because # '$' alone matches '\n', not '\r\n'. Ignore '\$' (literal '$'). if (-not $UnixText) { $Pattern = $Pattern -replace '(?<!\\)\$', '\r$' } # Build an array of Regex options and create the Regex object. $opts = @() if (-not $CaseSensitive) { $opts += "IgnoreCase" } if ($MultiLine) { $opts += "Multiline" } if ($opts.Length -eq 0) { $opts += "None" } $regex = new-object Text.RegularExpressions.Regex $Pattern, $opts } process { # The list of items to iterate depends on the parameter set name. switch ($PSCmdlet.ParameterSetName) { "Path" { $list = $Path } "LiteralPath" { $list = $LiteralPath } } # Iterate the items in the list of paths. If an item does not exist, # continue to the next item in the list. foreach ($item in $list) { if (-not (test-pathEx $item)) { write-error "Unable to find '$item'." continue } # Iterate each item in the path. If an item is not a file, # skip all remaining items. foreach ($file in get-childitemEx $item) { if ($file -isnot [IO.FileInfo]) { write-error "'$file' is not in the file system." break } # Get a temporary file name in the file's directory and create # it as a empty file. If set-content fails, continue to the next # file. Better to fail before than after reading the file for # performance reasons. if ($Overwrite) { $tempname = get-tempname $file.DirectoryName set-content $tempname $NULL -confirm:$FALSE if (-not $?) { continue } write-verbose "Created file '$tempname'." } # Read all the text from the file into a single string. We have # to do it this way to be able to search across line breaks. try { write-verbose "Reading '$file'." $text = [IO.File]::ReadAllText($file.FullName) write-verbose "Finished reading '$file'." } catch [Management.Automation.MethodInvocationException] { write-error $ERROR[0] continue } # If -Overwrite not specified, output the result of the Replace # method and continue to the next file. if (-not $Overwrite) { $regex.Replace($text, $Replacement) continue } # Do nothing further if we're in 'what if' mode. if ($WHATIFPREFERENCE) { continue } try { write-verbose "Writing '$tempname'." [IO.File]::WriteAllText("$tempname", $regex.Replace($text, $Replacement), [Text.Encoding]::$Encoding) write-verbose "Finished writing '$tempname'." write-verbose "Copying '$tempname' to '$file'." copy-item $tempname $file -force:$Force -erroraction Continue if ($?) { write-verbose "Finished copying '$tempname' to '$file'." } remove-item $tempname if ($?) { write-verbose "Removed file '$tempname'." } } catch [Management.Automation.MethodInvocationException] { write-error $ERROR[0] } } # foreach $file } # foreach $item } # process end { } } |