linux - Recursively look for files with a specific extension

Question

I'm trying to find all files with a specific extension in a directory and its subdirectories with my bash (Latest Ubuntu LTS Release).

This is what's written in a script file:

#!/bin/bash

directory="/home/flip/Desktop"
suffix="in"

browsefolders ()
  for i in "$1"/*; 
  do
    echo "dir :$directory"
    echo "filename: $i"
    #   echo ${i#*.}
    extension=`echo "$i" | cut -d'.' -f2`
    echo "Erweiterung $extension"
    if     [ -f "$i" ]; then        

        if [ $extension == $suffix ]; then
            echo "$i ends with $in"

        else
            echo "$i does NOT end with $in"
        fi
    elif [ -d "$i" ]; then  
    browsefolders "$i"
    fi
  done
}
browsefolders  "$directory"

Unfortunately, when I start this script in terminal, it says:

[: 29: in: unexpected operator

(with $extension instead of 'in')

What's going on here, where's the error? But this curly brace

Answer 1

find $directory -type f -name "*.in"

is a bit shorter than that whole thing (and safer - deals with whitespace in filenames and directory names).

Your script is probably failing for entries that don't have a . in their name, making $extension empty.