Computer Science
PASSMASS(1) PASSMASS(1)
NAME
passmass - change password on multiple machines
SYNOPSIS
passmass [ host1 host2 host3 ... ]
INTRODUCTION
Passmass changes a password on multiple machines. If you
have accounts on several machines that do not share pass-
word databases, Passmass can help you keep them all in
sync. This, in turn, will make it easier to change them
more frequently.
When Passmass runs, it asks you for the old and new pass-
words. (If you are changing root passwords and have
equivalencing, the old password is not used and may be
omitted.)
Passmass understands the "usual" conventions. Additional
arguments may be used for tuning. They affect all hosts
which follow until another argument overrides it. For
example, if you are known as "libes" on host1 and host2,
but "don" on host3, you would say:
passmass host1 host2 -user don host3
Arguments are:
-user
User whose password will be changed. By
default, the current user is used.
-rlogin
Use rlogin to access host. (default)
-slogin
Use slogin to access host.
-telnet
Use telnet to access host.
-program
Next argument is taken as program to run to set
password. Default is "passwd". Other common
choices are "yppasswd" and "set passwd" (e.g.,
VMS hosts). A program name such as "password
fred" can be used to create entries for new
accounts (when run as root).
-prompt
Next argument is taken as a prompt suffix pat-
tern. This allows the script to know when the
shell is prompting. The default is "# " for
root and "% " for non-root accounts.
-timeout
Next argument is number of seconds to wait for
responses. Default is 30 but some systems can
be much slower logging in.
HOW TO USE
The best way to run Passmass is to put the command in a
one-line shell script or alias. Whenever you get a new
account on a new machine, add the appropriate arguments to
the command. Then run it whenever you want to change your
passwords on all the hosts.
CAVEATS
It should be obvious that using the same password on mul-
tiple hosts carries risks. In particular, if the password
can be stolen, then all of your accounts are at risk.
Thus, you should not use Passmass in situations where your
password is visible, such as across a network where hack-
ers are known to eavesdrop.
On the other hand, if you have enough accounts with dif-
ferent passwords, you may end up writing them down some-
where - and that can be a security problem. Funny story:
my college roommate had an 11"x13" piece of paper on which
he had listed accounts and passwords all across the Inter-
net. This was several years worth of careful work and he
carried it with him everywhere he went. Well one day, he
forgot to remove it from his jeans, and we found a per-
fectly blank sheet of paper when we took out the wash the
following day!
SEE ALSO
"Exploring Expect: A Tcl-Based Toolkit for Automating
Interactive Programs" by Don Libes, O'Reilly and Associ-
ates, January 1995.
AUTHOR
Don Libes, National Institute of Standards and Technology
7 October 1993 1
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