sudo apt-get install makepasswd

makepasswd --chars 16 --count 7
88mCpPSqU8TW92cI
3HPpuSnFEGPwAyij
rEaYNRPbhBByPtwT
WhgoJAKs2iCYhYpr
PCsMx7A9JY3SGRVr
Hd4PU9vRIKhnhG8L
1QQNpn3JAo086oJW

makepasswd v1.10, a utility to generate and/or encrypt passwords.
 
Copyright (c) 1997-1999 by Rob Levin <levin@openproject.net>.  All rights are reserved by    
the author.  This program may be used under the terms of version 2 of the
GNU Public License.
 
Last modified on Monday, 7 April 1999 at 22:56 (UCT).
 
Format:          makepasswd [option...]
 
Options are:
 
--chars=N        Generate passwords with exactly N characters (do not use with
                       options --minchars and --maxchars).
--clearfrom=FILE Use a clear password from FILE instead of generating passwords.
                       Requires the --crypt or --crypt-md5 option; may not be
                       used with options --chars, --maxchars, --minchars,
                       --count, --string, --nocrypt.  Trailing newlines are
                       ignored, other whitespace is not.
--count=N        Produce a total of N passwords (the default is one).
--crypt          Produce encrypted passwords.
--crypt-md5      Produce encrypted passwords using the MD5 digest (hash)
                       algorithm.
--cryptsalt=N    Use crypt() salt N, a positive number <= 4096.  If random
                       seeds are desired, specify a zero value (the default).
--help           Ignore other operands and produce only this help display.
--maxchars=N     Generate passwords with at most N characters (default=10).
--minchars=N     Generate passwords with at least N characters (default=8).
--nocrypt        Do not encrypt the generated password(s) (the default).
--noverbose      Display no labels on output (the default).
--randomseed=N   Use random number seed N, between 0 and 2^32 inclusive.  A zero
                       value results in a real-random seed.  This option
                       generates predictable passwords, and should normally
                       be avoided.
--rerandom=N     Set the random seed value every N values used.  Specify zero
                       to use a single seed value (the default).  Specify
                       one to get true-random passwords, but plan on hitting
                       the CONTROL key a lot while it's running. ;)
--repeatpass=N   Use each password N times (4096 maximum, --crypt or
                       --crypt-md5 must be set and --cryptsalt may not be set).
--string=STRING  Use the characters in STRING to generate random passwords.
--verbose        Display labelling information on output.