Improve Command.swift (#4)

Sources/Command.swift

@@ -1,11 +1,38 @@
 import Darwin
 
-func excuteCommand(argments args: [String]) {
+func executeCommand(argments args: [String]) -> [String]? {
+    var pipe: [Int32] = [0, 0]
+    Darwin.pipe(&pipe)
+
     var fileActions: posix_spawn_file_actions_t? = nil
     posix_spawn_file_actions_init(&fileActions)
 
+    posix_spawn_file_actions_addopen(&fileActions, 0, "/dev/null", O_RDONLY, 0)
+    posix_spawn_file_actions_adddup2(&fileActions, pipe[1], 1)
+
+    posix_spawn_file_actions_addclose(&fileActions, pipe[0])
+    posix_spawn_file_actions_addclose(&fileActions, pipe[1])
+
     let argv: [UnsafeMutablePointer<CChar>?] = args.map{ $0.withCString(strdup) }
     var pid = pid_t()
     posix_spawnp(&pid, argv[0], &fileActions, nil, argv + [nil], nil)
     posix_spawn_file_actions_destroy(&fileActions)
+
+    close(pipe[1])
+
+    let N = 4096
+    var buf = [Int8](repeating: 0, count: N + 1)
+
+    var n: Int
+    var outputStrings = [String]()
+    repeat {
+        n = read(pipe[0], &buf, N)
+        if let output = String(validatingUTF8: buf) {
+            outputStrings.append(output)
+        }
+    } while n > 0
+
+    close(pipe[0])
+
+    return outputStrings
 }

Sources/Readmemd.swift

@@ -1,12 +1,10 @@
-import Darwin
-
 let readmeFileName = "README.md"
 
 /// Do not overwrite an existing file.
 func duplicateExistingReadme(existingReadmeDirctoryPath sourcePath: String, newReadmeDirectoryPath targetPath: String) {
-    excuteCommand(argments: ["cp", "-n", "\(sourcePath)/\(readmeFileName)", targetPath])
+    executeCommand(argments: ["cp", "-nv", "\(sourcePath)/\(readmeFileName)", targetPath])
 }
 
 func replaceStringsInReadme(source: String, target: String) {
-    excuteCommand(argments:["sed", "-i", "", "-e", "s/\(source)/\(target)/g", "./\(readmeFileName)"])
+    executeCommand(argments:["sed", "-i", "", "-e", "s/\(source)/\(target)/g", "./\(readmeFileName)"])
 }