Several commands accept password arguments, typically using
the passin and the passout options, respectively,
for input and output passwords. These arguments allow the password
to be obtained from a variety of sources. Both options take a single
argument in the following format. If no password argument is given
and a password is required, then the user is prompted to enter a
password. The password is read from the current terminal with echoing
The actual password is password.
Since the password is visible to utilities (such as the ps utility
in UNIX), use this form only when security is not important.
Obtains the password from the environment variable var.
Because the environment of other processes is visible on certain
platforms (such as ps in certain UNIX operating
systems), use this option with caution.
The first line of pathname is
the password. If the same pathname argument is
supplied to the passin and passout arguments,
then the first line is used for the input password and the next
line is used for the output password. The pathname need
not refer to a regular file; for example, it could refer to a device
or named pipe.
Reads the password from the file descriptor number.
This can be used, for example, to send the data via a pipe.
Reads the password from standard input.