mjhjmtu

I have many files in a folder. I want to concatenate all these files to a single file. For example cat * > final_file; But this will increase disk space and also will consume time. Is there is a way where I can hardlink/softlink all the files to final_file? For example ln * final_file.

With links, I'm afraid, this will not be possible. However, you could use a
named pipe. Example:

# create some dummy files
echo alpha >a
echo beta >b
echo gamma >c

# create named pipe
mkfifo allfiles

# concatenate files into pipe
cat a b c >allfiles

The last call will block until some process reads from the pipe and then exit. For a continuous operation one can use a loop, which waits for a process to read and starts over again.

while true; do
 cat a b c >allfiles
done

This is not possible.

N files mean N inodes. Hard links, by definition, are simply different names for the same inode. Symlinks are files that point to a certain inode (their target). Either way, soft or hard, the link can refer to a single inode.

In a straight way, no ...
You cannot hard/soft link to a single file. links are nothing more and nothing less than pointer from one file to another.

Now if you are worried about space and want to release the space you can do the following:

for i in *
do
 cat < "$i" >> destination_file &&
 rm -f -- "$i"
done

Basically, it will append the output to destination_file and remove the file afterwards. Also I'm assuming you don't need the original files.