fix: properly handle multiline strings in command converter

- Added detection for multiline strings to avoid incorrect conversion
- Multiline strings now have newlines escaped as \n instead of being joined with semicolons
- Line continuations (backslash) are properly distinguished from multiline strings
- Added comprehensive test cases for multiline string handling
- Fixes issue where multiline strings were incorrectly converted with semicolons

src/utils/__tests__/multilineCommandConverter.spec.ts

@@ -267,6 +267,54 @@ echo "three"`
 				expect(result.command).toContain('echo "Line 99"')
 				expect(result.command.split(";").length).toBeGreaterThan(50)
 			})
+
+			it("should handle multiline strings correctly", () => {
+				const input = `echo "This is a
+multiline
+string"`
+				const result = convertMultilineToSingleLine(input)
+				expect(result.success).toBe(true)
+				expect(result.command).toBe('echo "This is a\\nmultiline\\nstring"')
+			})
+
+			it("should handle multiline strings with single quotes", () => {
+				const input = `echo 'First line
+Second line
+Third line'`
+				const result = convertMultilineToSingleLine(input)
+				expect(result.success).toBe(true)
+				expect(result.command).toBe("echo 'First line\\nSecond line\\nThird line'")
+			})
+
+			it("should handle mixed commands with multiline strings", () => {
+				const input = `echo "Start"
+MESSAGE="This is
+a multiline
+message"
+echo "$MESSAGE"`
+				const result = convertMultilineToSingleLine(input)
+				expect(result.success).toBe(true)
+				expect(result.command).toBe(
+					'echo "Start" ; MESSAGE="This is\\na multiline\\nmessage" ; echo "$MESSAGE"',
+				)
+			})
+
+			it("should handle escaped quotes in strings", () => {
+				const input = `echo "Line with \\"escaped\\" quotes
+and a new line"`
+				const result = convertMultilineToSingleLine(input)
+				expect(result.success).toBe(true)
+				expect(result.command).toBe('echo "Line with \\"escaped\\" quotes\\nand a new line"')
+			})
+
+			it("should handle commands after multiline strings", () => {
+				const input = `TEXT="Line 1
+Line 2"
+echo "Done"`
+				const result = convertMultilineToSingleLine(input)
+				expect(result.success).toBe(true)
+				expect(result.command).toBe('TEXT="Line 1\\nLine 2" ; echo "Done"')
+			})
 		})
 
 		describe("Real-world examples", () => {

src/utils/multilineCommandConverter.ts

@@ -20,6 +20,142 @@ function hasHereDocument(command: string): boolean {
 	return hereDocPattern.test(command)
 }
 
+/**
+ * Detects if a command contains a multiline string literal
+ */
+function hasMultilineString(command: string): boolean {
+	// First check if the command has line continuations - these are NOT multiline strings
+	// Line continuations end with backslash
+	if (/\\\s*\n/.test(command)) {
+		return false
+	}
+
+	// Check for multiline strings in quotes that span multiple lines
+	// This is a simplified check - looks for quotes with newlines between them
+	const lines = command.split("\n")
+	let inString = false
+	let stringDelimiter = ""
+	let escapeNext = false
+
+	for (const line of lines) {
+		for (let i = 0; i < line.length; i++) {
+			const char = line[i]
+
+			if (escapeNext) {
+				escapeNext = false
+				continue
+			}
+
+			if (char === "\\") {
+				escapeNext = true
+				continue
+			}
+
+			if ((char === '"' || char === "'") && !inString) {
+				inString = true
+				stringDelimiter = char
+			} else if (char === stringDelimiter && inString) {
+				inString = false
+				stringDelimiter = ""
+			}
+		}
+		// If we're still in a string after processing a line, it's multiline
+		if (inString && lines.indexOf(line) < lines.length - 1) {
+			return true
+		}
+	}
+
+	return false
+}
+
+/**
+ * Converts multiline strings to single-line with escaped newlines
+ */
+function convertMultilineStrings(command: string): string {
+	// Handle multiline strings by replacing newlines with \n
+	const lines = command.split("\n")
+	const result: string[] = []
+	let inString = false
+	let stringDelimiter = ""
+	let currentString = ""
+	let beforeString = "" // Track text before the string starts
+	let escapeNext = false
+
+	for (let lineIndex = 0; lineIndex < lines.length; lineIndex++) {
+		const line = lines[lineIndex]
+		let processedLine = ""
+
+		for (let i = 0; i < line.length; i++) {
+			const char = line[i]
+
+			if (escapeNext) {
+				// We're escaping this character
+				if (inString) {
+					currentString += "\\" + char
+				} else {
+					processedLine += "\\" + char
+				}
+				escapeNext = false
+				continue
+			}
+
+			if (char === "\\") {
+				// This might be an escape character
+				const nextChar = i < line.length - 1 ? line[i + 1] : ""
+				if (nextChar === '"' || nextChar === "'") {
+					// It's escaping a quote
+					escapeNext = true
+					continue
+				} else {
+					// It's just a backslash
+					if (inString) {
+						currentString += char
+					} else {
+						processedLine += char
+					}
+				}
+			} else if ((char === '"' || char === "'") && !inString) {
+				// Starting a string
+				inString = true
+				stringDelimiter = char
+				beforeString = processedLine // Save text before string
+				currentString = char
+				processedLine = "" // Clear processed line as we're now in a string
+			} else if (char === stringDelimiter && inString) {
+				// Ending a string
+				currentString += char
+				processedLine = beforeString + currentString + processedLine
+				inString = false
+				stringDelimiter = ""
+				currentString = ""
+				beforeString = ""
+			} else if (inString) {
+				// Inside a string
+				currentString += char
+			} else {
+				// Outside a string
+				processedLine += char
+			}
+		}
+
+		if (inString && lineIndex < lines.length - 1) {
+			// We're in a multiline string, add \n for the newline
+			currentString += "\\n"
+		} else if (!inString && processedLine) {
+			// Not in a string, add the processed line
+			result.push(processedLine)
+		}
+	}
+
+	// If we're still in a string at the end, complete it
+	if (inString && currentString) {
+		// Close the unclosed string and add it with the text before it
+		result.push(beforeString + currentString)
+	}
+
+	return result.join("\n")
+}
+
 /**
  * Main function to convert multiline commands to single line
  * Uses a simple approach: join lines with semicolons for most cases
@@ -39,6 +175,24 @@ export function convertMultilineToSingleLine(command: string): ConversionResult
 		}
 	}
 
+	// Check if command contains multiline strings
+	if (hasMultilineString(command)) {
+		// Convert multiline strings to single-line with \n
+		try {
+			const converted = convertMultilineStrings(command)
+			// After converting strings, check if there are still multiple lines
+			if (!converted.includes("\n")) {
+				return { success: true, command: converted }
+			}
+			// If there are still multiple lines after string conversion,
+			// continue with normal processing
+			command = converted
+		} catch (error) {
+			// If string conversion fails, continue with normal processing
+			console.log(`[multilineCommandConverter] String conversion failed: ${error.message}`)
+		}
+	}
+
 	try {
 		// Simple approach: handle common patterns
 		let result = command