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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 REDHAT

script

SCRIPT(1)						    BSD General Commands Manual 						 SCRIPT(1)

NAME

     script -- make typescript of terminal session

SYNOPSIS

     script [-a] [-f] [-q] [-t] [file]

DESCRIPTION

     Script makes a typescript of everything printed on your terminal.	It is useful for students who need a hardcopy record of an interactive
     session as proof of an assignment, as the typescript file can be printed out later with lpr(1).

     If the argument file is given, script saves all dialogue in file.	If no file name is given, the typescript is saved in the file typescript.

     Options:

     -a      Append the output to file or typescript, retaining the prior contents.

     -f      Flush output after each write. This is nice for telecooperation: One person does `mkfifo foo; script -f foo' and another can super-
	     vise real-time what is being done using `cat foo'.

     -q      Be quiet.

     -t      Output timeing data to standard error. This data contains two fields, separated by a space. The first field indicates how much time
	     elapsed since the previous output. The second field indicates how many characters were output this time. This information can be used
	     to replay typescripts with realistic typing and output delays.

     The script ends when the forked shell exits (a control-D to exit the Bourne shell (sh(1)), and exit, logout or control-d (if ignoreeof is not
     set) for the C-shell, csh(1)).

     Certain interactive commands, such as vi(1), create garbage in the typescript file.  Script works best with commands that do not manipulate
     the screen, the results are meant to emulate a hardcopy terminal.

ENVIRONMENT

     The following environment variable is utilized by script:

     SHELL  If the variable SHELL exists, the shell forked by script will be that shell. If SHELL is not set, the Bourne shell is assumed. (Most
	    shells set this variable automatically).

SEE ALSO

     csh(1) (for the history mechanism), replay(1).

HISTORY

     The script command appeared in 3.0BSD.

BUGS

     Script places everything in the log file, including linefeeds and backspaces.  This is not what the naive user expects.

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