~/MyDir
    |__ file1.txt
    |__ file2.txt
    |__ file3.txt
    |__ ...
    |__ file30.txt


##</code><code>##

 
@sel_files = ( "file2.txt", "file4.txt", "file15.txt");

##</code><code>##

$ cat file2.txt file4.txt file15.txt > selected.txt