my lame attempt at a shell script...

Erik Norgaard norgaard at
Mon Jan 3 13:34:18 PST 2005

Eric F Crist wrote:

> elif [ "$grog_firewall_enable" <> "YES" or "NO" ]
> then
>         echo "Syntax error in /etc/rc.conf file. grog_firewall_enable 
> must be YES or NO"
> fi

I don't know if you're on 5.x, nor whether you use ipfw, ipfilter or pf 
- I wrote a replacement for ipfilter as I got dizzy trying to maintain a 
  too long ruleset so I wanted to split it into multiple files.

On 5.x things get a lot simpler. In /etc/rc.d there are plenty of 
scripts to look at - don't look at rc.firewall.

The scripts in /etc/rc.d are executed as ordered by rcorder(8).

Create your script and load rc.subr:

. /etc/rc.subr

which gives you a lot of predefined handy functions. Set the "name" 
variable in the script, eg:

name="grog" # Name of my firewall script

it is customary to call the script the same. Follow by


most scripts then just includes the line

run_rc_command "$1"

- everything is defined by the functions in rc.subr. Now, you can set 
the commands to be run and define them in your script, see eg. ipfilter.

rc.subr also contains a "checkyesno" function answering your question 
above - however, it is normal to check "[Yy][Ee][Ss]" and treat 
everything else as a no. After all, what are you gonna do if you only 
accept "yes" or "no" but some one typed "yeah right"? You must have a 
default action.

Since your script isn't default, maybe don't add default settings to 
/etc/defaults/rc.conf. Instead variables can have defaults eg:
${ipfilter_program:-/sbin/ipf} will use /sbin/ipf unless the 
ipfilter_program variable is set.

Finally, don't use bash, use /bin/sh and nothing else, you don't know if 
bash is available when your script run.

Regarding your script, which I got deleted from this mail (sorry), I 
think there is an error:

 > if [ "$grog_firewall_enable" = "YES" ]

this "=" is assignment and will always evaulate to true. You want

if [ "$grog_firewall_enable" -eq "YES" ]

I'm not sure if "==" works, but always be careful you're not using 
asignment in if-statements.

Cheers, Erik
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