Bruce Momjian <pgman@candle.pha.pa.us> writes:
>> echo is a builtin in ksh and derivatives, but I don't think it's safe
>> to assume it is a builtin everywhere...
> I believe it is safe. csh and sh have it built in. Does anyone know of
> a shell that does not have echo builtin? How do you tell? Not sure.
I looked at the man pages for plain old Bourne shell on the oldest
systems I have access to (SunOS 4.1.4 and HPUX 9). They all say that
echo is a builtin. So I guess it's probably safe enough. There may
be a few hoary old machines whereecho "ALTER USER ... $password ..." | backend
is a security risk, but it seems like it should be a very minimal
problem. (Especially since even a non-builtin echo should be a live
process for only a *really* short interval, even if the backend takes
longer to process the command.)
regards, tom lane