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Full Discussion: [SHELL: /bin/sh] For loop using variable variable names
Top Forums Shell Programming and Scripting [SHELL: /bin/sh] For loop using variable variable names Post 302651899 by Vryali on Wednesday 6th of June 2012 10:24:56 AM
Old 06-06-2012
[SOLVED] [SHELL: /bin/sh] For loop using variable variable names
Simple enough problem I think, I just can't seem to get it right.

The below doesn't work as intended, it's just a function defined in a much larger script:
Code:
CheckValues() {
    for field in \
        Group_ID \
        Group_Title \
        Rule_ID \
        Rule_Severity \
        Rule_Version \
        Rule_Title \
        Rule_Fix_Text; do
        if [ ! -n \$${field} ]; then
            echo "Error, ${field} undefined."
        else
            echo "\$${field}"
        fi
    done
}

The else statement won't exist once I've successfully tested it. The output I see when I run the actual script is:

Code:
# ./GEN000290-1.sh
$Group_ID
$Group_Title
$Rule_ID
$Rule_Severity
$Rule_Version
$Rule_Title
$Rule_Fix_Text
GEN000290-1: Running CMD: grep -c '^games' /etc/passwd
0
Not a finding.
GEN000290-1: Not a finding.

What I expect to see in the above is the value of those variables (Which is just a string of text assuming non-zero length).

Code:
Group_ID='V-4269-1'
Group_Title='Unnecessary Accounts, Games.'
Rule_ID='SV-4269-lr4_rule'
Rule_Severity='CAT II'
Rule_Version='GEN000290-1'
Rule_Title='The system must not have the unnecessary "games" account.'
Rule_Fix_Text='Remove the "games" account from the /etc/password file before connecting a system to the network.'

Kindly note that I need it to be /bin/sh compliant, as it'll be going across multiple Linux/Unix platforms.
Last edited by Vryali; 06-06-2012 at 11:47 AM.. Reason: Clarity
 

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LEARN ABOUT DEBIAN

setuid

SETUID(1)						      General Commands Manual							 SETUID(1)

NAME

       setuid - run a command with a different uid.

SYNOPSIS

       setuid username|uid   command [ args ]

DESCRIPTION

       Setuid  changes	user id, then executes the specified command.  Unlike some versions of su(1), this program doesn't ever ask for a password
       when executed with effective uid=root.  This program doesn't change the environment; it only changes the uid and then uses execvp() to find
       the command in the path, and execute it.  (If the command is a script, execvp() passes the command name to /bin/sh for processing.)

       For example,
	      setuid  some_user  $SHELL
       can be used to start a shell running as another user.

       Setuid  is  useful  inside  scripts that are being run by a setuid-root user -- such as a script invoked with super, so that the script can
       execute some commands using the uid of the original user, instead of root.  This allows unsafe commands (such as editors and pagers) to	be
       used  in  a  non-root  mode inside a super script.  For example, an operator with permission to modify a certain protected_file could use a
       super command that simply does:
	      cp protected_file temp_file
	      setuid $ORIG_USER ${EDITOR:-/bin/vi} temp_file
	      cp temp_file protected_file
       (Note: don't use this example directly.	If the temp_file can somehow be replaced by another user, as might be the case if it's kept  in  a
       temporary  directory,  there  will  be a race condition in the time between editing the temporary file and copying it back to the protected
       file.)

AUTHOR

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