F="io-testfile";
del()=system(Str("rm -f ", F));
del()
write(F, 123)
write(F, 456)
write1(F, "a",7)
write1(F, "b")
write(F)
writetex(F, 1/2)
readstr(F)
del()
\\
write(F, 1)
write(F, "1+2")
readvec(F)
del()
\\
writebin(F,1)
read(F)
del()
writebin(F)
read(F)
del()
L=List();writebin(F,L)
read(F)
del()
\\
write(F,"1+1")
extern("cat "F)
externstr("cat "F)
del()
{
  my(f=fileopen(F,"w"));
  for(i=1,10, filewrite(f,i));
  fileclose(f);
  my(f=fileopen(F,"a"));
  for(i=1,10, filewrite1(f,i); fileflush(f));
  filewrite1(f,"\n");
  fileclose(f);
  my(i=0,l,f=fileopen(F));
  while(l=fileread(f),
    print(i++,":",eval(l)));
  fileclose(f);
  my(i=0,l,f=fileopen(F,"r"));
  while(l=filereadstr(f),
    print(i++,":",l));
  fileflush();
  fileclose(f);
}
my(f=fileopen(F));fileclose(f);fileread(f)
my(f=fileopen(F));fileclose(f);filereadstr(f)
my(f=fileopen(F));fileclose(f);filewrite(f,"b")
my(f=fileopen(F));fileclose(f);filewrite1(f,"b")
my(f=fileopen(F));fileclose(f);fileflush(f)
my(f=fileopen(F,"w"));fileread(f)
my(f=fileopen(F,"a"));filereadstr(f)
my(f=fileopen(F));filewrite(f,"b");
my(f=fileopen(F,"r"));filewrite1(f,"b");
fileflush('x)
