Bash script, array not getting created as expected

Question

I'm pretty new to bash scripting and I'm obviously missing some fairly basic understanding as I can't work out why this script isn't doing as I'd expect. I've made a simple example reproducing the problem, it is supposed to make 3 folders, with 3 folders inside, then touch a file `test` inside of each. Here's the script: ``` #!/bin/sh DIR_LEVEL_1=("1" "2" "3") for DIR_1 in ${DIR_LEVEL_1[@]}; do mkdir $DIR_1 DIR_LEVEL_2=("$DIR_1/a" "$DIR_1/b" "$DIR_1/c") echo $DIR_LEVEL_2 for DIR_2 in ${DIR_LEVEL2[@]}; do mkdir $DIR_2 touch "$DIR_2/test" done done ``` The problem I was having was the it wasn't entering the second for loop, I put in that echo and it looks like the second array isn't being created properly as the output of the script is: ``` 1/a 2/a 3/a ``` which is just the first element of the array. running with `-xv` flag I get this, which shows it's taking no notice of that nested for loop (I guess because the array didn't get created as I wanted?) ``` #!/bin/sh DIR_LEVEL_1=("1" "2"…

Accepted Answer

Well, the real issue with your script is that you create `DIR_LEVEL_2`, but you iterate over `DIR_LEVEL2`. (Note the underscore difference). However, you also neglect to quote `"${array[@]}"`, which means it will not wordsplit properly. All that aside, might I suggest you use brace expansion to make this entire thing a better experience?

```
#!/bin/bash

dirs=( {1,2,3}/{a,b,c} )
mkdir -p "${dirs[@]}"
for d in "${dirs[@]}"; do
    touch "$d/test"
done
```

Edit/postscript: I notice your script above uses `#!/bin/sh`, but you've tagged this post `bash`. They are not the same thing. Unless you're certain you want to trade the greater featureset of bash for the greater portability of sh, use `#!/bin/bash`.

Bash script, array not getting created as expected

Solution

Problem