memtool linux command

Hi
Im using the DE1 soc board , and i want to transfer data from FPGA to HPS ddr3 memory and to do that i need to take the FPGA SDRAM port out of reset using command "memtool" : memtool -32 0xFFC25080=0x110
https://support.criticallink.com/redmine/projects/mityarm-5cs/wiki/Writing_to_HPS_Memory

but the command returns in the putty terminal command not found

I need your help