TAR operation not working with variable in filename

Question

# Current date
now=`date +%Y-%m-%d:%H:%M`

# Compress folder
tar czf "$now.tar.gz" dump/

does not work. No tar is created. But

tar czf someName.tar.gz dump/

works fine. Can someone point out the problem? It seems that

tar czf "$now.tar.gz" dump/

is not accepted as filename. Any ideas?

Answer 1

Found the problem:

If the archive file name includes a colon (‘:’), then it is assumed to be a file on another machine[...]

which lays here

now=`date +%Y-%m-%d:%H:%M`

I replaced the : with - and it works fine. More info here: http://www.gnu.org/software/tar/manual/html_section/tar_46.html#file