Axel and Aria2 are download accelerators that you use from the terminal and can speed up downloads significantly. I’ve not really found either to be better than the other and both are very easy to install and use.
Installation:
Axel with Debian/Ubuntu
apt-get install axel
CentOS/RHEL
yum install axel
Operation:
From the terminal run axel and the URL e.g. axel http://example.com/system.iso
There are a number of syntax switches that you can run depending on your requirements, such as:
–max-speed=x -s x Specify maximum speed (bytes per second)
–num-connections=x -n x Specify maximum number of connections
–output=f -o f Specify local output file
–search[=x] -S [x] Search for mirrors and download from x servers
–header=x -H x Add header string
–user-agent=x -U x Set user agent
–no-proxy -N Just don’t use any proxy server
–quiet -q Leave stdout alone
–verbose -v More status information
–alternate -a Alternate progress indicator
–help -h This information
–version -V Version information