issues looping over array in bash - arrays

Question

I have written a very simple port scanning script in bash. For my ports argument, i accept a single port (eg: 443), a comma-separated list (eg: 80,443), or a range (eg: 1-1000).
When I run my script with a single port or comma-separated list of ports, everything runs as it should:
~/projects/bash-port-scan# ./bash-port-scan.sh -i xx.xx.xxx.xxx -p 1,80,443 -v
Beginning scan of xx.xx.xxx.xxx
Port 1 closed
Port 80 open
Port 443 open
Scan complete.
~/projects/bash-port-scan# ./bash-port-scan.sh -i xx.xx.xxx.xxx -p 80 -v
Beginning scan of xx.xx.xxx.xxx
Port 80 open
Scan complete.
However, when I run with a range, I get:
~/projects/bash-port-scan# ./bash-port-scan.sh -i xx.xx.xxx.xxx -p 1-10 -v
Beginning scan of xx.xx.xxx.xxx
Port 1
2
3
4
5
6
7
8
9
10 closed
Scan complete.
Relevant code where I assign the array:
portarray=()
if [[ "$ports" == *","* ]]; then
IFS=','
read -r -a portarray <<< $ports
IFS=' '
elif [[ "$ports" == *"-"* ]]; then
IFS='-'
read -r -a range <<< $ports
IFS=' '
first="${range[0]}"
last="${range[1]}"
portarray=($(seq $first 1 $last))
else
portarray=($ports)
fi
and the loop itself:
empty=""
for p in "${portarray[#]}"; do
result=$(nc -zvw5 $ip $p 2>&1 | grep open)
if [ "$result" = "$empty" ]; then
if [ $verbose -eq 1 ]; then
str="Port "
closed=" closed"
echo "$str$p$closed"
fi
else
str="Port "
closed=" open"
echo "$str$p$closed"
fi
done
I'm not sure if this is because of how I'm assigning my port array, or if it is because of something I have wrong in my loop. I'm relatively new to bash scripting, and I'm having a terrible time figuring out what I have wrong.
I've read here on SO about some commands run in loops eating the output of other portions of the script, but I don't believe that to be the case here, as the script does actually print to screen, just not as expected.
EDIT:
Here is the full script:
#!/bin/bash
verbose=0
while [ "$1" != "" ]; do
case "$1" in
-h | --help )
echo "bash-port-scan.sh v0.1\r\nUsage: ./bash-port-scan.sh -i 127.0.0.1 -p 80,443\r\n./bash-port-scan.sh -i 127.0.0.1 -p 1-1000"; shift;;
-v | --verbose )
verbose=1; shift;;
-i | --ip )
ip="$2"; shift;;
-p | --ports )
ports="$2"; shift;;
esac
shift
done
if [[ $ip = "" ]]; then
echo "Please enter an IP address with -i"
exit
fi
if [[ $ports = "" ]]; then
echo "Please enter the port(s) with -p"
exit
fi
portarray=()
if [[ "$ports" == *","* ]]; then
IFS=','
read -r -a portarray <<< $ports
IFS=' '
elif [[ "$ports" == *"-"* ]]; then
IFS='-'
read -r -a range <<< $ports
IFS=' '
first="${range[0]}"
last="${range[1]}"
portarray=($(seq $first $last))
else
portarray=($ports)
fi
if [ $verbose -eq 1 ]; then
echo "Beginning scan of $ip"
fi
shuf -e "${portarray[#]}"
empty=""
for p in "${portarray[#]}"; do
result=$(nc -zvw5 $ip $p 2>&1 | grep open)
if [ "$result" = "$empty" ]; then
if [ $verbose -eq 1 ]; then
str="Port "
closed=" closed"
echo "$str$p$closed"
fi
else
str="Port "
closed=" open"
echo "$str$p$closed"
fi
done
echo "Scan complete."

Answer 1

Addressing just the portarray=(...) assignment (when ports=1-10)
Consider:
$ first=1
$ last=10
$ portarray=($(seq $first 1 $last))
$ typeset -p portarray
declare -a portarray=([0]=$'1\n2\n3\n4\n5\n6\n7\n8\n9\n10')
NOTE: the output from the $(seq ...) call is processed as a single string with embedded linefeeds.
A couple ideas:
### define \n as field separator; apply custom IFS in same line to limit IFS change to just the follow-on array assignment:
$ IFS=$'\n' portarray=($(seq $first 1 $last))
$ typeset -p portarray
declare -a portarray=([0]="1" [1]="2" [2]="3" [3]="4" [4]="5" [5]="6" [6]="7" [7]="8" [8]="9" [9]="10")
### use mapfile to read each *line* into a separate array entry:
$ mapfile -t portarray < <(seq $first 1 $last)
$ typeset -p portarray
declare -a portarray=([0]="1" [1]="2" [2]="3" [3]="4" [4]="5" [5]="6" [6]="7" [7]="8" [8]="9" [9]="10")