Repetitive Tasks: using if..then inside a loop - Shell Programming and Scripting

garak · #1 (**permalink**) 03-09-2006

I thought I was getting pretty good with Bash but this problem is stumping me. Any suggestions would be greatly appreciated. I've written a firewall script that uses a lot of functions. The variables are read into the script from another .conf file earlier on in the code. Most of these variables are either set as "ON", "OFF", or as an IP address. To date, I've written out a conditional statement for each service. Here is an example of two of them:

if [ $FTP = "ON" ]; then
FTP_WAN
else
if [ "$FTP" != "OFF" ]; then
FTP_PORT_FORWARDING
fi
fi

if [ $SSH = "ON" ]; then
SSH_WAN
else
if [ "$SSH" != "OFF" ]; then
SSH_PORT_FORWARDING
fi
fi

I'd like to figure out a way to make one conditional statement inside a loop where the $SSH or $FTP variables are replaced for each variable corresponding to a service.

I'd thought something like:

$SERVICES=SSH,FTP

for VAR in $SERVICES; do

if [ $VAR = "ON" ]; then
$VAR_WAN
else
if [ "$VAR" != "OFF" ]; then
$VAR_PORT_FORWARDING
fi
fi

done

But no variation I've tried seems to work. I want it to
input the variable, like SSH, and then read the value
of SSH inside the conditional statement. Am I missing
some brackets somewhere or anything else?

Thanks.

vgersh99 · #2 (**permalink**) 03-09-2006

shell != perl

Code:

SERVICES='SSH FTP'

Code:

#!/bin/ksh

a='ssh ftp'

for i in ${a}
do
   eval echo \${i}_wan
done

thestevew · #3 (**permalink**) 03-13-2006

How about:

Code:

# Test values
ssh=on
ftp=off
# End test values

typeset -u v               ;# output in upper case

a='ssh ftp'

for i in ${a}
do
  eval v=\${$i}            ;# v becomes value of variable _called_ $i
  if [ $v = 'ON' ]; then
    v=${i}_WAN
  else
    v=${i}_PORT_FORWARDING
  fi

  print $v                 ;# do something with the output
done

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