Gzip not working depending on command line parameter

[wildestpixel]

Post compression seems to work with some commands but not others, backing up from ssd as /dev/sda :

WORKS
sudo imgclone -s /dev/sda -d /home/pi/mnt/Main/Raspbian/backupimages/argon.img -gzip
Outcome - Completes making .img file and then proceeds to make .gz file succesfully

DOESN'T WORK
sudo imgclone -s /dev/sda -d /home/pi/mnt/Main/Raspbian/backupimages/$(hostname).backup.$(date +%Y%m%d%H%M).img -gzip
Outcome - Completes making .img file but doesnt attempt to make gz file.

Obviously would be nice to datestamp these in the file name as well as the attributes

Also - if a gzipped image already exists with the filename chosen, would be good to be able to switch so that it force overwrites rather than having to select yes manually at the terminal.

[tom-2015]

I've added force overwrite options but don't know why the gzip fails. Is there a space in $(hostname)? What if you put the -gzip option at the beginning (before -s)?

I've added command that prints if gzip/bzip compress option is turned on at the start of the application.

[wildestpixel]

Can confirm no spaces in hostname
Moving argument -gzip to the beginning does not fix the parsing of it
The gzip forcing works nicely (thanks), however looks like bzip2 with -f argument is problematic on large archives?