rwos

    $ rm -rf /
    rm: it is dangerous to operate recursively on ‘/’
    rm: use --no-preserve-root to override this failsafe

  from os import*
  r='s=[0]*8**5'
  p=0
  for c in read(0,9**9):r+='\n'+' '*p+dict(zip("><+-.,[","p+=1|p-=1|s[p]+=1|s[p]-=1|write(1,chr(s[p]))|s[p]=ord(read(0,1))|while s[p]:".split('|'))).get(c,'');p+=c in'[]'and 92-ord(c)
  exec r