Concatenate specific files into one single file

Question

In a folder containing X files, I need to concatenate Y files (where X > Y) together into a single text file. I have the filenames (of Y files) that I need to concatenate.

Can anyone please help me out on how to concatenate these files?

Answer 1

You can use the cat command (see man cat for more information) to concatenate the text files.

If you want to create a new file

# cat [FILE1] [FILE2]... > new_file

or if you want to append to an existing file use it like this

# cat [FILE1] [FILE2]... >> file 

Answer 2

If the Y filenames are listed in a list file, a simple combination of xargs and cat is enough:

xargs cat <list >>concatenation_of_files

In the case you've been careful and you've listed files one per line (to avoid problems with spaces in filenames), then just add a -d delimiter option:

xargs -d'\n' cat <list >>concatenation_of_files

(This assumes concatenation_of_files is initially inexistent or empty).