ispy | iSpy Client | Development Tools library

• &, the call operator, is situationally required for invocation of commands (including external executables), namely if the command is specified via a quoted string and/or a variable or expression, possibly as _part of an expandable (interpolating) string ("...").

  • However, it's safe to always use &

• To programmatically pass multiple arguments to external executables, use an array.

  • Be sure to make each argument its own array element; that is, use $array = '-n', 'noiseprof' and not $array = '-n noiseprof' - the latter would be passed as "-n noiseprof", i.e. as a single, double-quoted argument.

• Except in edge cases due to legacy bugs relating to values with embedded " chars. and empty strings - see this answer - do not enclose arguments in escaped " chars., e.g. "`"$var`"" - if the value of $var contains spaces, PowerShell will automatically double-quoted it behind the scenes.

• Do not use Invoke-Expression, which should generally be avoided, to invoke external programs - see this answer.

Applied to your case: