Strange behavior on fresh Debian installation

Mon Feb 4 10:34:15 UTC 2019

Hello list,

I'm having strange behaviour on fresh install of Debian 9
After I login and work for  a while then any command on bash terminal is
missing with message such as the following
bash: ls command not found

I tried googling and found no solution for this.
I wonder if anyone having the same issue and know how to solve it.

Note"
- The same problem also appear on Knoppix live CD

System:
Debian 9 x86-64

Best Regards
-- 
Edhoari Setiyoso