System Initiative

/* * Copyright (c) Meta Platforms, Inc. and affiliates. * * This source code is licensed under both the MIT license found in the * LICENSE-MIT file in the root directory of this source tree and the Apache * License, Version 2.0 found in the LICENSE-APACHE file in the root directory * of this source tree. */ package main import ( "flag" "io" "log" "os" ) func main() { var outputFile = flag.String("output", "", "help message for flag n") flag.Parse() inputFiles := flag.Args() if *outputFile == "" || len(inputFiles) < 2 { log.Fatal("usage: concat_files.go --output out.txt in1.txt in2.txt") } f, err := os.Create(*outputFile) if err != nil { log.Fatal(os.Stderr, "Error creating output file: %v", err) } defer f.Close() for _, file := range inputFiles { infile, err := os.Open(file) if err != nil { log.Fatal(os.Stderr, "Error opening input file %s: %v", file, err) } defer infile.Close() _, err = io.Copy(f, infile) if err != nil { log.Fatal("Error copying file %s: %v\n", file, err) } } }