Looping over IP addresses from a file using bash array

Question

I have a file in which I have given all the IP addresses. The file looks like following:

[asad.javed@tarts16 ~]#cat file.txt
10.171.0.201
10.171.0.202
10.171.0.203
10.171.0.204
10.171.0.205
10.171.0.206
10.171.0.207
10.171.0.208

I have been trying to loop over the IP addresses by doing the following:

launch_sipp () {
        readarray -t sipps < file.txt
        for i in "${!sipps[@]}";do
                ip1=(${sipps[i]})
                echo $ip1
                sip=(${i[@]})
                echo $sip
        done

But when I try to access the array I get only the last IP address which is 10.171.0.208. This is how I am trying to access in the same function launch_sipp() :

local sipp=$1
echo $sipp
Ip=(${ip1[*]})
echo $Ip

Currently I have IP addresses in the same script and I have other functions that are using those IPs:

launch_tarts () {
        local tart=$1
        local ip=${ip[tart]}

        echo "    ----  Launching Tart $1  ----  "
        sshpass -p "tart123" ssh -Y -X -L 5900:$ip:5901 tarts@$ip <<EOF1
        export DISPLAY=:1
        gnome-terminal -e "bash -c \"pwd; cd /home/tarts; pwd; ./launch_tarts.sh exec bash\""
        exit
EOF1
}

kill_tarts () {
        local tart=$1
        local ip=${ip[tart]}

        echo "    ----  Killing Tart $1  ----   "
        sshpass -p "tart123"  ssh -tt -o StrictHostKeyChecking=no tarts@$ip <<EOF1
        . ./tartsenvironfile.8.1.1.0
        nohup yes | kill_tarts mcgdrv &
        nohup yes | kill_tarts server &
        pkill -f traf
        pkill -f terminal-server
        exit
EOF1
}

ip[1]=10.171.0.10
ip[2]=10.171.0.11
ip[3]=10.171.0.12
ip[4]=10.171.0.13
ip[5]=10.171.0.14

case $1 in
        kill) function=kill_tarts;;
        launch) function=launch_tarts;;
        *) exit 1;;
esac

shift

for ((tart=1; tart<=$1; tart++)); do
       ($function $tart) &
       ips=(${ip[tart]})
       tarts+=(${tart[@]})
done
wait

How can I use different list of IPs for a function created for different purpose from a file?

Answer 1

How about using GNU parallel? It's an incredibly powerful wonderful-to-know very popular free linux tool, easy to install.

For example,

$ parallel echo {} :::: ips.txt 
10.171.0.202
10.171.0.201
10.171.0.203
10.171.0.204
10.171.0.205
10.171.0.206
10.171.0.207
10.171.0.208

But you can replace echo with just about any as complex series of commands as you can imagine / calls to other scripts. Parallel loops through the input it receives, and performs (in parallel) the same operation on each input.

Answer 2

In pure Bash:

#!/bin/bash
while read ip; do
    echo "$ip"
    # ...
done < file.txt

Or in parallel:

#!/bin/bash
while read ip; do
    (
        sleep "0.$RANDOM" # random execution time
        echo "$ip"
        # ...
    ) &
done < file.txt
wait