Bash Script elif Not Triggering - bash

Question

I could use some help figuring out why the elif in the following script is not working. The first part of the if works, and the else part of the statement works, but the elif does not. In other words, when I login as 'root' I get the DNS address I am expecting. And if I log in as Guest, I get the DNS address I was expecting, but not if I login as any of the students listed in the elif.
#!/bin/bash
\# Setting DNS by User
\# Get variables. $3 is logging in user.
user=$3
\# Root and Admin should be wide open
if [ $user = "root" ] || [ $user = "admin" ]; then
networksetup -setdnsservers Wi-Fi 8.8.8.8
networksetup -setdnsservers Ethernet 8.8.8.8
\# Older students get an open, but filtered experience:
elif
\# Adams class
[ $user = "Student01" ] ||
[ $user = "Student02" ] ||
[ $user = "Student03" ] ||
[ $user = "Student04" ] ||
\# Mariannes class:
[ $user = "Student05" ] ||
[ $user = "Student06" ] ||
[ $user = "Student07" ] ||
[ $user = "Student08" ]
then
networksetup -setdnsservers Wi-Fi 8.8.4.4
networksetup -setdnsservers Ethernet 8.8.4.4
\# Everyone else gets whitelisted DNS
else
networksetup -setdnsservers Wi-Fi 208.67.222.222
networksetup -setdnsservers Ethernet 208.67.222.222
fi
exit 0

Answer 1

My first thought is this is not really a maintainable approach. This is (in
my opinion) not the way to use the if / elif / if / fi structure.
That said, I have going to throw some advanced script at you that will do what
you want and is far more supportable.
First, I recommend keeping admin and student names in bash arrays. Eventually,
you can populate those arrays from another source (such as a file: shown in
comments). This will make the if / elif tests much simpler as shown.
#! /usr/bin/env bash
# Setting DNS by User
# Get variables. $3 is logging in user.
user=$3
# admin_list=$HOME/admin.list
# declare -a admins
# if [[ -f "$admin_list" ]] ; then
# IFS=$'\n' read -d '' -r -a admins < <(sed -e 's/#.*$//' "$admin_list")
#
# wait $! || return $?
# else
# echo "$admin_list not found: skipping"
# fi
declare -a admins=( root admin )
# special_list=$HOME/special.list
# declare -a special
# if [[ -f "$special_list" ]] ; then
# IFS=$'\n' read -d '' -r -a special < <(sed -e 's/#.*$//' "$special_list")
#
# wait $! || return $?
# else
# echo "$special_list not found: skipping"
# fi
declare -a special=(
# Adams class
"Student01"
"Student02"
"Student03"
"Student04"
# Mariannes class:
"Student05"
"Student06"
"Student07"
"Student08"
)
# Root and Admin should be wide open
if [[ " ${admins[#]} " =~ " $user " ]] ; then
echo Admin
# networksetup -setdnsservers Wi-Fi 8.8.8.8
# networksetup -setdnsservers Ethernet 8.8.8.8
elif [[ " ${special[#]} " =~ " $user " ]] ; then
# Older students get an open, but filtered experience:
# Adams class
echo Special
# networksetup -setdnsservers Wi-Fi 8.8.4.4
# networksetup -setdnsservers Ethernet 8.8.4.4
else
echo "Everyone else"
# Everyone else gets whitelisted DNS
# networksetup -setdnsservers Wi-Fi 208.67.222.222
# networksetup -setdnsservers Ethernet 208.67.222.222
fi
exit 0
Note: I commented out the nerworksetup from your script and added an echo
for each condition for testing. You can remove the echo lines and uncomment the
networksetup lines.
I tested it as:
$ script a1 a2 root
Admin
$ script a1 a2 Student02
Special
$ script a1 a2 Student1000
Everyone else
I hope this helps.