how to search a list of files with filename in a folder using regex code example

Example 1: linux replace string in files recursively

find . -type f -name "*.txt" -exec sed -i'' -e 's/foo/bar/g' {} +

Example 2: linux replace string in all files

sed -i 's/old-text/new-text/g' input.txt

Example 3: python script to read all file names in a folder

import os

def get_filepaths(directory):
    """
    This function will generate the file names in a directory 
    tree by walking the tree either top-down or bottom-up. For each 
    directory in the tree rooted at directory top (including top itself), 
    it yields a 3-tuple (dirpath, dirnames, filenames).
    """
    file_paths = []  # List which will store all of the full filepaths.

    # Walk the tree.
    for root, directories, files in os.walk(directory):
        for filename in files:
            # Join the two strings in order to form the full filepath.
            filepath = os.path.join(root, filename)
            file_paths.append(filepath)  # Add it to the list.

    return file_paths  # Self-explanatory.

# Run the above function and store its results in a variable.   
full_file_paths = get_filepaths("/Users/johnny/Desktop/TEST")

Example 4: C# get all files in directory

//path is the path of the directory to get files from
//searchPattern is to get specific files. If you want only exe files you enter *.exe

private static IEnumerable<string> GetAllFiles(string path, string searchPattern)
        {
            return Directory.EnumerateFiles(path, searchPattern).Union(
            Directory.EnumerateDirectories(path).SelectMany(d =>
            {
                try
                {
                    return GetAllFiles(d, searchPattern);
                } catch(Exception e)
                {
                    return Enumerable.Empty<string>();
                }
            }));
        }