Provide shell and escape options when formatting matching files

src/main.ts

@@ -6,9 +6,9 @@ import {Webhooks} from '@octokit/webhooks'
 import {Filter, FilterResults} from './filter'
 import {File, ChangeStatus} from './file'
 import * as git from './git'
-import shellEscape from './shell-escape'
+import {escape, shellEscape} from './shell-escape'
 
-type ExportFormat = 'none' | 'json' | 'shell'
+type ExportFormat = 'none' | 'json' | 'shell' | 'escape'
 
 async function run(): Promise<void> {
   try {
@@ -201,6 +201,8 @@ function serializeExport(files: File[], format: ExportFormat): string {
   switch (format) {
     case 'json':
       return JSON.stringify(fileNames)
+    case 'escape':
+      return fileNames.map(escape).join(' ')
     case 'shell':
       return fileNames.map(shellEscape).join(' ')
     default:
@@ -209,7 +211,7 @@ function serializeExport(files: File[], format: ExportFormat): string {
 }
 
 function isExportFormat(value: string): value is ExportFormat {
-  return value === 'none' || value === 'shell' || value === 'json'
+  return value === 'none' || value === 'shell' || value === 'json' || value === 'escape'
 }
 
 run()

src/shell-escape.ts

@@ -1,5 +1,28 @@
-// Uses easy safe set of characters which can be left unescaped to keep it readable.
-// Every other character will be backslash-escaped
-export default function shellEscape(value: string): string {
+// Backslash escape every character except small subset of definitely safe characters
+export function escape(value: string): string {
   return value.replace(/([^a-zA-Z0-9,._+:@%/-])/gm, '\\$1')
 }
+
+// Returns filename escaped for usage as shell argument.
+// Applies "human readable" approach with as few escaping applied as possible
+export function shellEscape(value: string): string {
+  if (value === '') return value
+
+  // Only safe characters
+  if (/^[a-zA-Z0-9,._+:@%/-]+$/m.test(value)) {
+    return value
+  }
+
+  if (value.includes("'")) {
+    // Only safe characters, single quotes and white-spaces
+    if (/^[a-zA-Z0-9,._+:@%/'\s-]+$/m.test(value)) {
+      return `"${value}"`
+    }
+
+    // Split by single quote and apply escaping recursively
+    return value.split("'").map(shellEscape).join("\\'")
+  }
+
+  // Contains some unsafe characters but no single quote
+  return `'${value}'`
+}