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taijidude
taijidude

Posted on • Edited on

Golang Working With Files...

#go #cli #beginners

Today a short one again. I have played around with some go again and wanted to write it down. There are multiple options to some of the stuff i did. So this is not a comprehensive guide.

Check if file exists

func fileExists(fileName string) (bool, error) { info, err := os.Stat(fileName) if err != nil { if os.IsNotExist(err) { return false, nil } else { return false, err } } return !info.IsDir(), nil }
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Create a file and write text to it

created, err = os.Create("test.txt") if err != nil { log.Fatal(err) } //write to text file //i ignore the number of bytes writen here _, err = created.WriteString("Hello World") if err != nil { log.Fatal(err) } //Close the file so it can be used later created.Close()
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Learned a lesson here. In my first version i wrote defer created.close(). But than later ran into problems, when i wanted to read from the file. So you need to close the file if you want to read from it in the same function.

Delete a file

created, err = os.Create("toDelete.txt") if err != nil { log.Fatal(err) } created.Close() err := os.Remove("toDelete.txt") if err != nil { log.Fatal(e) }
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Read from a text file - 1

anotherFile, err := os.Open("anotherFile.txt") if err != nil { log.Fatal(err) } scanner := bufio.NewScanner(anotherFile) for scanner.Scan() { fmt.Println(scanner.Text()) } if err := scanner.Err(); err != nil { log.Fatal(err) }
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Read from a text file - 2

content, err := os.ReadFile(fileName) if err != nil { log.Fatal(err) } //The content is a []byte because of that: string(...) fmt.Println(string(content)) }
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Not much to adress here. I slowy see the verbosity of go. Haven't made up my mind about the language yet.

Copy or move a file

//copy a file bytesRead, err := ioutil.ReadFile("fileToCopy.txt") if err != nil { log.Fatal(err) } ioutil.WriteFile("cptrgt/CopyTarget.txt", bytesRead, os.ModePerm) //Move a file err = os.Rename("oldFile.txt", "cptrgt/newFile.txt") if err != nil { log.Fatal(err) }
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Don't like how to move a file. Not a catastrophe but also not really intuitive either. Have not tested the copy speeds yet.

Create and recursivly delete a Folder

//create a new Folder if err := os.Mkdir("cptrgt", os.ModePerm); err != nil { log.Fatal(err) } //delete a folder recursively err := os.RemoveAll("cptrgt") if err != nil { log.Fatal(err) }
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After my last post i was happy a about the syntax but now i stumble more and mor about how verbose it is. Honestly i would say i'm not sold on go for quick commandline tools. I see the great performance and simple deployment, but at the moment i wouldn't trade it for python, java or the powershell. But i will keep learning and maybe i will be convinced.

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