Passing string included dollar signs to -Replace Variable

Question

I am trying to replace a sentence in .config file using powershell.

${c:Web.config} = ${c:Web.config} -replace

\'$BASE_PATH$\\

Answer 1

Just to provide a bit more background to stej's answer, there are two things going on here:

1) While parsing the command, powershell is expanding the variables in the string arguments to -replace (for example, the string "shell: $ShellId" will expand the ShellId variable, producing shell: Microsoft.PowerShell). Using the backtick escape character, or declaring the string with single quotes, prevents this (both "shell: `$ShellId" and 'shell: $ShellId' become shell: $ShellId).

2) The -replace operator uses .NET regular expressions, where the $, \, and . characters are special language elements. Using the backslash escape character allows special characters to be treated as literal values within the regular expression (e.g. \$ will match a dollar character, while $ will match the end of the line). Since $ is used by both powershell and regular expressions, it has to be escaped twice (using either "\`$" or '\$').

In this case, another alternative would be to use the string.Replace method, which will perform a case-sensitive replacement:

${c:Web.config}.Replace(
  '$BASE_PATH$\Test\bin$Test_TYPE$\WebTest.dll',
  'c:\program Files\example\webtest.dll'
)