PowerShell multiple string replacement efficiency

Question

I\'m trying to replace 600 different strings in a very large text file 30Mb+. I\'m current building a script that does this; following this Question:

Script:

Answer 1

Combining the hash technique from Adi Inbar's answer, and the match evaluator from Keith Hill's answer to another recent question, here is how you can perform the replace in PowerShell:

# Build hashtable of search and replace values.
$replacements = @{
  'something0' = 'somethingelse0'
  'something1' = 'somethingelse1'
  'something2' = 'somethingelse2'
  'something3' = 'somethingelse3'
  'something4' = 'somethingelse4'
  'something5' = 'somethingelse5'
  'X:\Group_14\DACU' = '\\DACU$'
  '.*[^xyz]' = 'oO{xyz}'
  'moresomethings' = 'moresomethingelses'
}

# Join all (escaped) keys from the hashtable into one regular expression.
[regex]$r = @($replacements.Keys | foreach { [regex]::Escape( $_ ) }) -join '|'

[scriptblock]$matchEval = { param( [Text.RegularExpressions.Match]$matchInfo )
  # Return replacement value for each matched value.
  $matchedValue = $matchInfo.Groups[0].Value
  $replacements[$matchedValue]
}

# Perform replace over every line in the file and append to log.
Get-Content $filePath |
  foreach { $r.Replace( $_, $matchEval ) } |
  Add-Content 'C:\log.txt'