How to create a command sequence for this?


Recommended Posts

A. Write a command sequence, to create a directory structure like follows:

1. level 1 - 4 directories with random alphanumeric name of 8 characters each directory

2. level 2 - each level 1 directory will have 3 directories - yes, no and yesorno

3. level 3 - each level 3 directory will have 9 directories with directory named in series 1-9 e.g. [1, 2, 3...9]

4. level 4 - each level 4 directory will have 3 directories - yes, no and yesorno

5. all directories at each level will have a text file named abc.txt with random alpha numeric text of 200 characters

Can someone shed a light in a right direction that will help me to achieve this?

Thanks !!

I have a background in C#/VB.NET, so that will influence my answer:

You'll need a few nested For-Next loops to create the exact number of directories you need. You'll also need a pseudo-random number generator to generate the random alphanumeric characters, and to make the "yes, no, or yesorno" directories. The 1-9 directories are easy.

If you're using .NET, use a TextWriter to write the text files.

Have fun!

It could be done in pretty much any language, scripting or otherwise, but assuming you want it in bash:

#!/bin/bash

function random_chars ()
{
	tmp=$( < /dev/urandom tr -dc A-Za-z1-9 | head -c $1 )
	eval $2=$tmp
}

function create_abc ()
{
	local rand=''
	local file=$1'/abc.txt'

	random_chars 200 rand
	echo $rand > $file
	echo $file
}

function create_1to9 ()
{
	for i in 1 2 3 4 5 6 7 8 9
	do

		wd=$1'/'$i
		mkdir $wd
		echo $wd

		create_abc $wd
		create_yesno $wd 0

	done
}

function create_answer ()
{
	local answer=$1'/'$2

	mkdir $answer
	echo $answer

	create_abc $answer  

	if [ $3 == 1 ]
	then
		create_1to9 $answer
	fi
}

function create_yesno ()
{
	create_answer $1 'yes' $2
	create_answer $1 'no'  $2
	create_answer $1 'yesorno' $2
}

function create_dirs ()
{
	local ret=''

	for i in 1 2 3 4
	do
		random_chars 8 ret

		dir=$1'/'$ret
		mkdir $dir
		echo $dir

		create_abc $dir
		create_yesno $dir 1	  

	done

}

function main ()
{
	create_dirs $1
}

main $1

Copy/echo it into a file, chmod +x it.

Then to run:

./script targetdir

targetdir is where you want it to create the directory structure. I just used '.' ( current directory ) for testing.

My bash script knowledge is pretty awful, so I'm sure someone else could do better.

I have a background in C#/VB.NET, so that will influence my answer:

You'll need a few nested For-Next loops to create the exact number of directories you need. You'll also need a pseudo-random number generator to generate the random alphanumeric characters, and to make the "yes, no, or yesorno" directories. The 1-9 directories are easy.

If you're using .NET, use a TextWriter to write the text files.

Have fun!

That's about as efficient as using ice cream for a fire guard ;)

There was a slight bug in random_chars () that caused it to output the abc.txt file incorrectly. Change it to:

Edit: Actually, the tmp variable is superfluous. Just remove it entirely.

function random_chars ()
{
	eval $2=$( < /dev/urandom tr -dc A-Za-z1-9 | head -c $1 )
}

Thanks for your responses.. . .

I came up with following command sequence :::::::::::::


bash$ for i in $(seq 4); do mkdir `< /dev/urandom tr -dc A-Z0-9 | head -c8`; done

bash$ for i in `ls`; do `mkdir -p $i/{yes,no,yesorno}/{1..9} `; done

bash$ find . -type d -exec touch {}/abc.txt \;
[/CODE]

Now I am stuck at creating "yes,no,yesorno" directory in directories with name 1 - 9

This is what I tried ::

bash$ for i in $(find . -type d -name [1-9]); do `mkdir -p /{yes,no,yesorno}`;done

but its prompting with error "permission denied"

What am I missing?

Thanks for your responses.. . .

I came up with following command sequence :::::::::::::


bash$ for i in $(seq 4); do mkdir `< /dev/urandom tr -dc A-Z0-9 | head -c8`; done

bash$ for i in `ls`; do `mkdir -p $i/{yes,no,yesorno}/{1..9} `; done

bash$ find . -type d -exec touch {}/abc.txt \;
[/CODE]

Now I am stuck at creating "yes,no,yesorno" directory in directories with name 1 - 9

This is what I tried ::

bash$ for i in $(find . -type d -name [1-9]); do `mkdir -p /{yes,no,yesorno}`;done

but its prompting with error "permission denied"

What am I missing?

What's happening is you are trying to create the folders /yes, /no, and /yesorno, which are in the [i]root directory[/i] of your filesystem. What you want is to modify that line to be

[CODE]
for i in $(find . -type d -name [1-9]); do `mkdir -p $i/{yes,no,yesorno}`; done
[/CODE]

Basically, you're missing that $i which would make the {yes,no,yesorno} a subdirectory of your random folders as opposed to a subdirectory of the root directory.

  • Like 2

What's happening is you are trying to create the folders /yes, /no, and /yesorno, which are in the root directory of your filesystem. What you want is to modify that line to be


for i in $(find . -type d -name [1-9]); do `mkdir -p $i/{yes,no,yesorno}`; done
[/CODE]

Basically, you're missing that $i which would make the {yes,no,yesorno} a subdirectory of your random folders as opposed to a subdirectory of the root directory.

Thats what I needed. .. . .Thanks.. .

But now there are some other complications I am facing,,, :(

I need to redirect the output to [b]output.txt[/b] and error to [b]error.txt[/b]

[b]I came up with this:[/b]

[CODE]
for i in $(seq 4); do mkdir `< /dev/urandom tr -dc A-Z0-9 | head -c8`<&- 2>$HOME/error.txt; done

for i in `ls` ; do `mkdir -p $i/{yes,no,yesorno}/{1..9}` <&- 1>$HOME/output.txt 2>>$HOME/error.txt; done

for i in $(find . -type d -name [1-9]); do `mkdir -p $i/{yes,no,yesorno} <&- 1>$HOME/output.txt 2>>$HOME/error.txt `;done

for i in $(find . -type d); do `< /dev/urandom tr -dc A-Z0-9 | head -c200 > $i/abc.txt <&- 2>>$HOME/error.txt `; done
[/CODE]

After that, I need to join all the command sequences into one single command.

When I tried joining the commands and placing [b]done [/b]at the end, it seems to be something is missing.. please help

'done' indicates the end of a loop, not the end of a command sequence. 'joining' the command should be as simple as placing them all on one line with semicolons between them. Based on the four commands you quoted in your last post, your final command should look something like this:


for i in $(seq 4); do mkdir `< /dev/urandom tr -dc A-Z0-9 | head -c8`<&- 2>$HOME/error.txt; done; for i in `ls` ; do `mkdir -p $i/{yes,no,yesorno}/{1..9}` <&- 1>$HOME/output.txt 2>>$HOME/error.txt; done; for i in $(find . -type d -name [1-9]); do `mkdir -p $i/{yes,no,yesorno} <&- 1>$HOME/output.txt 2>>$HOME/error.txt `;done; for i in $(find . -type d); do `< /dev/urandom tr -dc A-Z0-9 | head -c200 > $i/abc.txt <&- 2>>$HOME/error.txt `; done
[/CODE]

  • Like 2

'done' indicates the end of a loop, not the end of a command sequence. 'joining' the command should be as simple as placing them all on one line with semicolons between them. Based on the four commands you quoted in your last post, your final command should look something like this:


for i in $(seq 4); do mkdir `< /dev/urandom tr -dc A-Z0-9 | head -c8`<&- 2>$HOME/error.txt; done; for i in `ls` ; do `mkdir -p $i/{yes,no,yesorno}/{1..9}` <&- 1>$HOME/output.txt 2>>$HOME/error.txt; done; for i in $(find . -type d -name [1-9]); do `mkdir -p $i/{yes,no,yesorno} <&- 1>$HOME/output.txt 2>>$HOME/error.txt `;done; for i in $(find . -type d); do `< /dev/urandom tr -dc A-Z0-9 | head -c200 > $i/abc.txt <&- 2>>$HOME/error.txt `; done
[/CODE]

Thank you. . .. Finally. .. :)

[CODE]
for i in $(seq 4); do mkdir `< /dev/urandom tr -dc A-Z0-9 | head -c8`<&- 2>$HOME/error.txt; done;for i in `ls`; do `mkdir -p $i/{yes,no,yesorno}/{1..9}` <&- 1>$HOME/output.txt 2>>$HOME/error.txt; done;for i in $(find . -type d -name [1-9]); do `mkdir -p $i/{yes,no,yesorno}` <&- 1>$HOME/output.txt 2>>$HOME/error.txt; done;for i in $(find . -type d); do `< /dev/urandom tr -dc A-Z0-9 | head -c200 > $i/abc.txt` <&- 2>>$HOME/error.txt; done
[/CODE]

I tried to edit the above post but can't see the edit button, ,, :(

btw, can we redirect the output of mkdir command to a file? i.e output.txt . . .coz its always empty.

And when I execute the command twice, I get an error "Unable to create a directory abc.txt"

How can I make this command to be executed "n" number of times?. . .I don't want to loop it . .. I need to execute the same command on the previous output it generated.

Now I can see the edit button. .

I think your problem is that mkdir doesn't actually output anything to screen unless it encounters an error; so redirecting its output to a file is virtually useless. If you really want it to print a message, try passing it the -v switch. As for the second part of your question about executing the command 'n' times, I have no idea what you are talking about. My best guess is that you want to create a directory inside of a directory that does not yet exist. To create any intermediate directories you could pass mkdir the -p switch. Putting all of the above together your command may look something like the following:


mkdir -pv 'rar' 1>output.txt 2>&1
[/CODE]

This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Posts

    • I do trust Apple probably more than these other companies with certain data, but I also do think (and it has been demonstrated that) Apple pulls a lot of shenanigans and always has for a long time.
    • Does your iPhone support the latest iOS version? Here's the iOS 27 compatibility list by Aditya Tiwari It's that time of year when we get to know about the latest operating system updates for Apple devices. For iPhone, Apple previewed the iOS 27 update at WWDC 2026, where the company finally introduced an upgraded version of Siri. Apple typically supports iPhone models for up to five years. But it has been making exceptions in recent years (read iPhone 11). If you're wondering whether your iPhone is compatible with the iOS 27 update, here is the official list of devices: iPhone 17 Pro Max, iPhone 17 Pro, iPhone 17, iPhone 17e, iPhone Air iPhone 16 Pro Max, iPhone 16 Pro, iPhone 16, iPhone 16 Plus, iPhone 16e iPhone 15 Pro Max, iPhone 15 Pro, iPhone 15 Plus, iPhone 15 iPhone 14 Pro Max, iPhone 14 Pro, iPhone 14 Plus, iPhone 14 iPhone 13 Pro Max, iPhone 13 Pro, iPhone 13, iPhone 13 mini iPhone 12 Pro Max, iPhone 12 Pro, iPhone 12, iPhone 12 mini iPhone 11 Pro Max, iPhone 11 Pro, iPhone 11 iPhone SE (2nd generation), iPhone SE (3rd generation) So, you can download the iOS 27 developer beta on up to 31 different iPhone models. There has been no change to the list of supported iPhones since iOS 26. However, it will expand to include more devices when the iPhone 18 series arrives later this year. To download the developer beta on your iPhone, go to Settings > General > Software Update > Beta Updates. Here, select "iOS 27 Developer Beta" from the list of choices to get the new update. In addition to iOS 27, you can try the developer beta versions of macOS 27, iPadOS 27, watchOS 27, tvOS 27, and HomePod software 27 on your supported devices. iOS 27 comes with improved Liquid Glass, which you can adjust using a new transparency slider. Apple said during the keynote that iPhone apps now launch up to 30% faster, new photos appear in the Photos app up to 70% faster, and AirDrop transfers work up to 80% faster. The new update promises to improve performance on older iPhones by introducing a new CPU Scheduler that supports devices all the way back to the iPhone 11. While iOS 27 is supported on older iPhones, it goes without saying that they'll lack several features due to hardware differences. For instance, iPhone 14/14 Plus and older models come with a notch instead of the Dynamic Island. Similarly, Apple Intelligence features are supported on iPhone 15 Pro/Pro Max and later models.
    • The Radeon RX 9070 XT is right up there with the GeForce RTX 5070 Ti
    • I don't know why someone said useless, but it does have that pesky kernel driver bundled, and it's in perennial turmoil. When it goes bad, it goes very bad, and it's impossible to predict when it will due to system differences. I know that they're in the middle of development for a major new version that will include a completely new driver, one that they expect will largely solve the problem, but that's a ways out and it's unproven at this point.
    • doesn't AdGuard let ads through that pay to be let through?
  • Recent Achievements

    • Experienced
      JayZJay went up a rank
      Experienced
    • Reacting Well
      Sir_Timbit earned a badge
      Reacting Well
    • Week One Done
      rubentuben8 earned a badge
      Week One Done
    • Week One Done
      ARaclen earned a badge
      Week One Done
    • Week One Done
      jojodbn earned a badge
      Week One Done
  • Popular Contributors

    1. 1
      +primortal
      524
    2. 2
      PsYcHoKiLLa
      232
    3. 3
      +Edouard
      132
    4. 4
      ATLien_0
      88
    5. 5
      Steven P.
      83
  • Tell a friend

    Love Neowin? Tell a friend!