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Name

autopw -- cache and re-inject passwords into other programs

Synopsis

autopw command

Desription

The autopw utility will cache passwords and re-inject them whenever the given command requires them. That is, if command prompts for a password, autopw will cache it and then provide that password the next time command asks for it.

autopw is frequently used to wrap commands invoking ssh(1) repeatedly to avoid having the user monitor the command and re-supply their password when other forms of automation are not possible.

Prompts Matched

autopw currently matches and distinguishes the following prompts: +o assword:

+o
Enter passphrase for
+o
Bad passphrase, try again
+o
Enter PEM pass phrase:
+o
Enter passphrase: +o y,n,(y/n)? +o ?,??,q +o (yes/no)?

In the latter examples, autopw will be affirmative instead of supplying a password.

Examples

The following examples illustrate common usage of this tool.

To invoke the command ‘foo.sh’ and have autopw cache and re-inject any passwords prompted for, run

autopw sh foo.sh

Caveats

Since autopw must keep the password available in memory it is obviously advised against using this tool on shared hosts.

You should only invoke commands that you actually trust -- autopw will only respond to specific patterns, and any program that prompts one of the strings autopw is looking for will be supplied with the given password. This is particularly concerning when executing commands on a remote, possibly untrusted host.

autopw does not play very well with multiple levels of pseudo-terminals (screen sessions, ‘ssh -t’ etc.) and may at times print the cleartext password to the terminal.

autopw invokes perl(1) ’s ‘pack/unpack’ function for each password provided/injected. This can become a performance-impacting limitation.

See Also

expect(1) , perl(1)

History

The autopw utility was originally written at Yahoo! Inc. It not being terribly original or clever, there appeared a number of variations. This variant is bundled with the scanmaster(1) scripts for convenience.


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