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Full Discussion: Injecting into shell history with perl?
Top Forums Shell Programming and Scripting Injecting into shell history with perl? Post 302525060 by turk451 on Wednesday 25th of May 2011 02:50:25 PM
Old 05-25-2011
Quote:
I have an old fashioned console (non-GUI) style perl program that asks dozens of questions. Incorporating readline might mitigate this a bit. What I would like to do is enhance the logic of this program to check ARGV before prompting the console (user) for information and then, after all the questions have been answered, artificially inject the completed command line into the shell history so the command can be re-run again with identical inputs by just hitting the up-arrow. This will save them from having to type all that stuff in again.
I don't think it's a good idea to hack the history to implement another hack in your program.

The ARGV stuff should be easy. Just check the length of ARGV array to see if you got enough command-line inputs. Also, you may want to validate the input data just as a good practice. Even if a user has supplied enough arguments, they could still be badly formatted. Also, be sure to display to the user what the inputs should be.

As for repeated executions of the same script with different inputs, you could easily modify the script to function in a loop, and provide some option for the used to update each value every time the loop runs. What I imagine is a prompt that will default to the previous values used for each parameter of the call, then ask for an updated value. If the user enters nothing, then it would just use the default. If the user enters some new value, it would use that new value.
 

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LEARN ABOUT HPUX

chsh

chsh(1) 						      General Commands Manual							   chsh(1)

NAME

       chsh - change default login shell

SYNOPSIS

       login-name [shell]

       login-name [shell]

       login-name [shell]

       login-name [shell]

DESCRIPTION

       The command changes the login-shell for a user's login name in the repository (see passwd(1)).

       The  DCE  repository is only available if Integrated Login has been configured; see auth.adm(1M).  If Integrated Login has been configured,
       other considerations apply.  A user with appropriate DCE privileges is capable of modifying a user's shell;  this  is  not  dependent  upon
       superuser privileges.

       If the repository is not specified (as in [login-name]), the login shell is changed in the file only.

       Run after running to make sure the information was processed correctly.

   Notes
       The  command  is  a hard link to the command. When is executed, actually the command gets executed with appropriate arguments to change the
       user login shell in the repository specified in command line. If no repository is specified, the login shell is changed in the file.

   Arguments
	      login-name  A login name of a user.

	      shell	  The absolute path name of a shell.  If the file exists, the new login shell must be listed in that file.  Otherwise, you
			  can specify one of the standard shells listed in the getusershell(3C) manual entry.  If shell is omitted, it defaults to
			  the POSIX shell,

   Options
       The following option is recognized:

	      Specify the repository to which the operation is to be applied.
		     Supported repositories include and

   Security Restrictions
       You must have appropriate privileges to use the optional login-name argument to change another user's login shell.

NETWORKING FEATURES

   NFS
       File can be implemented as a Network Information Service (NIS) database.

EXAMPLES

       To change the login shell for user to the default:

       To change the login shell for user to the C shell:

       To change the login shell for user to the Korn shell in the DCE registry:

WARNINGS

       If two or more users try to write the file at the same time, a passwd locking mechanism was devised.  If this locking  fails  after  subse-
       quent retrying, terminates.

AUTHOR

       was developed by HP and the University of California, Berkeley.

FILES

SEE ALSO

       chfn(1), csh(1), ksh(1), passwd(1), sh(1), sh-posix(1), getusershell(3C), pam(3), passwd(4), shells(4).

																	   chsh(1)
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