Hardlink/softlink multiple file to one file

cathard linksymlink

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.

Best Answer

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

Related Solutions

Concatenate specific files into one single file

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

Files Symlink – Convert a Hardlink into a Symbolic Link

I created a script that will do this. The script converts all hard-links it finds in a source directory (first argument) that are the same as in the working directory (optional second argument) into symbolic links:

https://gist.github.com/rubo77/7a9a83695a28412abbcd

It has an option -n for a dry-run, that doesn't do anything but shows what would be done.

Main part:

$WORKING_DIR=./
#relative source directory from working directory:
$SOURCE_DIR=../otherdir/with/hard-links/with-the-same-inodes

# find all files in WORKING_DIR
cd "$WORKING_DIR"
find "." -type f -links +1 -printf "%i %p\n" | \
  while read working_inode working_on
do
    find "$SOURCE_DIR" -type f -links +1 -printf "%i %p\n" | sort -nk1 | \
      while read inode file
    do
        if [[ $inode == $working_inode ]]; then
            ln -vsf "$file" "$working_on"
        fi
    done
done

The -links +1 --> Will find all files that have MORE than 1 link. Hardlinked files have a link count of at least two.

Best Answer

Related Solutions

Concatenate specific files into one single file

Files Symlink – Convert a Hardlink into a Symbolic Link

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