/powershell

Quoting and parser boundaries

Quoting and here-strings

• Single-quoted strings are literal; double-quoted strings expand variables, subexpressions, and PowerShell escape sequences.
• Use ${name} when the end of a variable name is ambiguous in an expandable string.
• A here-string opener (@' or @") must be followed by a newline. Its matching closing marker must be alone on a line. This skill recommends a column-one closer for broad parser compatibility; verify indentation behavior against the target PowerShell version.
• Single-quoted here-strings preserve $, $(), and backticks. Double-quoted here-strings expand them.

Parsing and special characters

• PowerShell parses expressions and command arguments differently. Prefer direct invocation with distinct argument values over constructing a command string, and validate untrusted values for the target program's option syntax.
• PowerShell 7.3 introduced $PSNativeCommandArgumentPassing modes (Legacy, Standard, and Windows). Defaults and compatibility behavior vary by platform and executable; Windows PowerShell 5.1 uses legacy behavior.
• The backtick introduces PowerShell escape sequences in expandable strings. The -- token only stops parameter parsing for PowerShell commands; native invocations receive it as an argument. The Windows-only --% token stops parsing at a native-command boundary and is not a general quoting fix.
• Each embedding layer (such as YAML, JSON, or another shell) can transform the script before PowerShell parses it. Validate the final PowerShell text, not just its outer representation.

Sources

• about_Quoting_Rules
• about_Parsing
• about_Special_Characters