Use process.platform to detect OS during postinstall

Gruntfile.js

@@ -390,13 +390,14 @@ module.exports = function (grunt) {
                 stdout: false,
             },
             fixCryptoApiImports: {
-                command: [
-                    `[[ "$OSTYPE" == "darwin"* ]]`,
-                    "&&",
-                    `find ./node_modules/crypto-api/src/ \\( -type d -name .git -prune \\) -o -type f -print0 | xargs -0 sed -i '' -e '/\\.mjs/!s/\\(from "\\.[^"]*\\)";/\\1.mjs";/g'`,
-                    "||",
-                    `find ./node_modules/crypto-api/src/ \\( -type d -name .git -prune \\) -o -type f -print0 | xargs -0 sed -i -e '/\\.mjs/!s/\\(from "\\.[^"]*\\)";/\\1.mjs";/g'`
-                ].join(" "),
+                command: function () {
+                    switch (process.platform) {
+                        case "darwin":
+                            return `find ./node_modules/crypto-api/src/ \\( -type d -name .git -prune \\) -o -type f -print0 | xargs -0 sed -i '' -e '/\\.mjs/!s/\\(from "\\.[^"]*\\)";/\\1.mjs";/g'`;
+                        default:
+                            return `find ./node_modules/crypto-api/src/ \\( -type d -name .git -prune \\) -o -type f -print0 | xargs -0 sed -i -e '/\\.mjs/!s/\\(from "\\.[^"]*\\)";/\\1.mjs";/g'`;
+                    }
+                },
                 stdout: false
             }
         },