Prepend prefix in tar

Question

I currently do in a shellscript very inefficiently:

cp -a $MYPATH /tmp/$VERSION
cd /tmp
tar cjf archive.tar.bz2 $VERSION

I want everything to be contained in the directory called $VERSION - is there a way to do this without having to copy everything as in the above script?

Answer 1

The GNU version of tar supports the --transform option (and its alias --xform), you could use it like this

tar --transform "s/^$MYPATH/$VERSION/" -cf archive.tar.bz2 "$MYPATH"

For example, given this directory tree

foo
└── foo.txt

the command

tar --transform "s/^foo/bar/" -cf foo.tar.bz2 foo

will produce an archive like

$ tar -tf foo.tar.bz2
bar/
bar/foo.txt

Answer 2

To tar the current directory and add a prefix, this worked for me:

tar --transform 's,^\.,$VERSION,' -cf foo.tar .

Answer 3

To add a directory prefix comfortably, use a different separator than / in the --transform argument, e.g. + or , like in Andy's answer.

So, for a simpler case, you have a bunch of files in current directory, and you don't want to create a tarbomb.

tar czf logs_nightly.tar.gz --tranform 's+^+logs_nightly/+' *.log

The syntax is s+search+replace+, and for ^ it simply matches the start of filename.

And now, just to answer the OP - well, you can avoid copying your whole directory to /tmp by running:

mv $MYPATH $VERSION
tar cjf archive.tar.bz2 $VERSION
mv $VERSION $MYPATH

Alternatively:

ln $MYPATH $VERSION
tar cjf archive.tar.bz2 $VERSION

(hard link, avoids problems with symlinks)

The last two were included for entertainment value, I myself would stick to toro2k's answer.

Answer 4

If you can get away without preserving symbolic links within the file tree you're tarring, you could do

ln -s $MYPATH /tmp/$VERSION
cd /tmp
tar cjhf archive.tar.bz2 $VERSION

The h option means dereference symlinks, i.e. include the file or directory that the link points to rather than simply recording the fact that there was a symlink and what it pointed to.