Coming from a Python background, I'm now learning Bash scripting. I am having a bit of trouble with a while loop. While trying to create a simple script that creates a new directory, the output behaves erratically.

In my first attempt using the script below:

#!/bin/bash
while :
do echo 'Enter directory name:' read newdir `mkdir $newdir` echo "[+] Directory created!" break if [ -d $newdir ];then echo "[-] cannot create directory. $newdir already exists." fi
done

The output is correct:

xuser@xuser-VB:~/Scripts$ ./newdir.sh
Enter directory name:
abc
[+] Directory created!

However, if I try to create a directory with the same name, it still outputs the [+] Directory created! on top of the system error message.

xuser@xuser-VB:~/Scripts$ ./newdir.sh
Enter directory name:
abc
mkdir: cannot create directory ‘abc’: File exists
[+] Directory created!

what am I missing or forgetting?

1 Answer

You need to check the existence of the directory before creating it.

#!/bin/bash
while :
do echo 'Enter directory name:' read newdir if [ -d "$newdir" ] ; then echo "[-] cannot create directory. $newdir already exists." continue fi mkdir -- "$newdir" echo "[+] Directory created!" break
done

I also removed the backquotes, mkdir doesn't output anything, so they aren't useful in this context.

Moreover, double quote variables - without double quotes, directory names containing spaces would not work.

Using mkdir -- "$newdir" will interpret the $newdir as the directory name even if it starts with a dash.

2

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