Create the directory structure using mkdir and touch

Question

I am learning Unix online and i came across this question to create a hierarchical structure. I have created the directories using mkdir command but I am stuck while creating the files inside directory.

My command for creating directories is

mkdir -p mydir/{colors/{basic,blended},shape,animals/{mammals,reptiles}}

Solution

Here's two ways to do it. There's more, but the concept would be the same: either extending what you have, or iterating over a list and breaking each list item into parts.

Long way to do it

There's nothing special that needs to be done with touch. Simply extend the same arguments that you had for mkdir command to include files.

bash-4.3$ mkdir -p mydir/{colors/{basic,blended},shape,animals/{mammals,reptiles}}
bash-4.3$ tree mydir
mydir
├── animals
│   ├── mammals
│   └── reptiles
├── colors
│   ├── basic
│   └── blended
└── shape

7 directories, 0 files
bash-4.3$ touch mydir/{colors/{basic/{red,blue,green},blended/{yellow,orange,pink}},shape/{circle,square,cube},animals/{mammals/{platipus,bat,dog},reptiles/{snakes,crocodile,lizard}}}
bash-4.3$ tree mydir
mydir
├── animals
│   ├── mammals
│   │   ├── bat
│   │   ├── dog
│   │   └── platipus
│   └── reptiles
│       ├── crocodile
│       ├── lizard
│       └── snakes
├── colors
│   ├── basic
│   │   ├── blue
│   │   ├── green
│   │   └── red
│   └── blended
│       ├── orange
│       ├── pink
│       └── yellow
└── shape
    ├── circle
    ├── cube
    └── square

Short way

If you observe, all of your directories have files to create. Thus what we can do is create list of items( effectively a bash array ) and iterate over them, with using mkdir with suffix removal and then touch. Like this:

bash-4.3$ arr=( mydir/{colors/{basic/{red,blue,green},blended/{yellow,orange,pink}},shape/{circle,square,cube},animals/{mammals/{platipus,bat,dog},reptiles/{snakes,crocodile,lizard}}} )
bash-4.3$ for i in "${arr[@]}"; do  mkdir -p "${i%/*}" && touch "$i"; done
bash-4.3$ tree mydir
mydir
├── animals
│   ├── mammals
│   │   ├── bat
│   │   ├── dog
│   │   └── platipus
│   └── reptiles
│       ├── crocodile
│       ├── lizard
│       └── snakes
├── colors
│   ├── basic
│   │   ├── blue
│   │   ├── green
│   │   └── red
│   └── blended
│       ├── orange
│       ├── pink
│       └── yellow
└── shape
    ├── circle
    ├── cube
    └── square

7 directories, 15 files

Side note: if you have spaces in any file or directory name, ensure that you single or double quote those items, e.g.:

arr=( mydir/{'with space',without_space/{file1,file2}} )

See also.

Comments

[Admin]

Well, what touch command(s) did you try? what happened?

[Admin]

I tried this; touch mydir/{colors/{basic/{red,blue,green},blended/{yellow,orange‌​,pink}}, shape,animals/{mammals/{pltypus,bat,dog},reptiles/{snakes,cr‌​ocodile,lizard}}}. But i am getting an error stating "Cannot touch : No such file or directory found"

[Admin]

Practical approach. 1. Try replacing touch by echo to see if there are typos in your command. 2. Try with smaller examples and make them bigger gradually until you find the issue.

[Admin]

A related question, from the same homework, is askubuntu.com/questions/916727 .

[Neeraj gupta]

I tried the first one but i am getting an error stating "Cannot touch : No such file or directory found". Please Help.