Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
Community Proposals
Community Proposals
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

Comments on How to list the first x files in each directory

Parent

How to list the first x files in each directory

+0
−0

MWE

With the following tree:

l1
└── l2
    ├── d0
    │   ├── f0
    │   ├── f1
    │   ├── f2
    │   ├── f3
    │   ├── f4
    │   └── f5
    ├── d1
    │   ├── f0
    │   ├── f1
    │   ├── f2
    │   ├── f3
    │   ├── f4
    │   └── f5
    ├── d2
    │   ├── f0
    │   ├── f1
    │   ├── f2
    │   ├── f3
    │   ├── f4
    │   └── f5
    ├── d3
    │   ├── f0
    │   ├── f1
    │   ├── f2
    │   ├── f3
    │   ├── f4
    │   └── f5
    ├── d4
    │   ├── f0
    │   ├── f1
    │   ├── f2
    │   ├── f3
    │   ├── f4
    │   └── f5
    └── d5
        ├── f0
        ├── f1
        ├── f2
        ├── f3
        ├── f4
        └── f5

8 directories, 36 files

created by this script:

#!/bin/bash

path=l1/l2

mkdir -p $path

for dir in {0..5}; do
    mkdir $path/d$dir

    for file in {0..5}; do
        touch $path/d$dir/f$file
    done
done

Problem

How do I list the first three files of each directory?

First three being the first three alphabetically sorted.

Desired output:

l1/l2/d0/f0
l1/l2/d0/f1
l1/l2/d0/f2
l1/l2/d1/f0
l1/l2/d1/f1
l1/l2/d1/f2
l1/l2/d2/f0
l1/l2/d2/f1
l1/l2/d2/f2
l1/l2/d3/f0
l1/l2/d3/f1
l1/l2/d3/f2
l1/l2/d4/f0
l1/l2/d4/f1
l1/l2/d4/f2
l1/l2/d5/f0
l1/l2/d5/f1
l1/l2/d5/f2

Tried

I can get each file via:

find l1 -mindepth 3 -maxdepth 3 -type f

but I can't find a way in the manual to specify the match depth.

The output from find is also unsorted, and so, the first three would not be the first three alphabetically.

Notes

My goal is to make a trimmed copy of a large dataset for preliminary, quick testing as I develop my code. Performing this trim within the code unnecessarily complicates the test code and will be a wasted effort as it will be removed for the real deal. Without it in place, I am able to test what will be the final product.

The real target using the real dataset may be sub directories and not files. In other words, "give me the the first 3 directories in level 2".

Ideally, if I can find a way to list the files, I can pipe them to a cp command.

History
Why does this post require moderator attention?
You might want to add some details to your flag.
Why should this post be closed?

0 comment threads

Post
+2
−0

Is this what you want?

Edit: Credit to Kamil Maciorowski‭ for catching an unsafe interpolation in the previous draft; it will work for non-adversarial inputs but this newer version is safer and a better example to learn from.

find l1 -mindepth 2 -maxdepth 2 \
  -type d \! -empty \ 
  -exec sh -c 'printf "%s\n" "$1"/* | head -n 3' _ {} \;
History
Why does this post require moderator attention?
You might want to add some details to your flag.

4 comment threads

Never embed `{}` in shell code (1 comment)
Questions (3 comments)
Potential simplifications (4 comments)
Works for me (1 comment)
Questions
mcp‭ wrote 7 months ago

I was struggling with piping in an -exec call. Where did you read about passing sh -c ""? I did not find that in the find manual.

mcp‭ wrote 7 months ago

How is this sorting the output properly? It returns the first three alphabetically, but how?

r~~‭ wrote 7 months ago

Piping is a shell feature. If you want to use shell features, you have to be running in a shell. The find manual isn't responsible for pointing that out.

It is specified that wildcards in shell scripts must expand in the order of the current locale.