Not able to execute commands and get the error "Cannot allocate memory"

Issue

• The system has enough memory, but when trying to execute commands, get the error "Cannot allocate memory".

  -bash-4.1# free -g
               total       used       free     shared    buffers     cached
  Mem:            94         43         51          0          0          0
  -/+ buffers/cache:         42         51
  Swap:           19          0         19
  
  -bash-4.1# uname -a
  -bash: fork: Cannot allocate memory