BASH Script that loops thru 4 different text files - bash

Question

I'm trying to create a BASH script that takes data from four different text files and assigns each line from each of the text files to a variable and then run a command using those variables. I already have a for loop constructed to do this task but the challenge I'm having is the for loop isn't doing one on one mapping.
I want this loop to iterate thru every line and run the command once per line and stop the loop when it reaches the EOF. When I run this script, I get the output as follows;
The username is jsmith The hostname is 0000-Ubuntu The description is P-Ubuntu The IP is 0.0.0.0/24
The username is jsmith The hostname is 0000-Ubuntu The description is P-Ubuntu The IP is 1.1.1.1/24
The username is jsmith The hostname is 0000-Ubuntu The description is P-Ubuntu The IP is 2.2.2.2/24
I need this to be one one one mapped; for example:
The username is jsmith The hostname is 0000-Ubuntu The description is P-Ubuntu The IP is 0.0.0.0/24
The username is pstone The hostname is 1111-Ubuntu The description is P-Ubuntu The IP is 1.1.1.1/24
The username is drogers The hostname is 3333-Ubuntu The description is P-Ubuntu The IP is 3.3.3.3/24
and so on....
As you can tell, I'm a newbie in bash scripting and I'd really appreciate any guidance/help.
Thanks!
#!/bin/bash
HOSTNAMES=$(cat /home/squadri/hostnames.txt)
DESCRIPTIONS=$(cat /home/squadri/descriptions.txt)
USERNAMES=$(cat /home/squadri/usernames.txt)
IPS=$(cat /home/squadri/ips.txt)
for i in $HOSTNAMES ; do
for j in $DESCRIPTIONS ; do
for k in $USERNAMES ; do
for l in $IPS ; do
echo "The username is $k"
echo "The hostname is $i"
echo "The description is $j"
echo "The IP is $l"
done
done
done
done

Answer 1

You can use the paste command for that:
paste /home/squadri/{hostnames,descriptions,usernames,ips}.txt |\
while read hostname description username ip; do
echo "The username is $username"
echo "The hostname is $hostname"
echo "The description is $description"
echo "The IP is $ip"
done
One potential pitfall with this approach is whitespace characters in your files but it should work fine if there are none in any of the lines in your files.

Answer 2

Read from 4 different file descriptors:
while IFS= read -r hostname;
IFS= read -r description <&3;
IFS= read -r username <&4;
IFS= read -r ip <&5; do
echo "The username is $username"
echo "The hostname is $hostname"
echo "The description is $description"
echo "The IP is $ip"
done < hostnames.txt 3< descriptions.txt 4< usernames.txt 5< ips.txt
Technically, this reads until the end of descriptions.txt, regardless of the length of the other files. To stop when the shortest file ends, join the commands with &&:
while IFS= read -r hostname &&
IFS= read -r description <&3 &&
IFS= read -r username <&4 &&
IFS= read -r ip <&5; do
echo "The username is $username"
echo "The hostname is $hostname"
echo "The description is $description"
echo "The IP is $ip"
done < hostnames.txt 3< descriptions.txt 4< usernames.txt 5< ips.txt
Iterating until you reach the end of the longest file is a little more complex (you can't simply join the commands with ||), so I'll leave it as an exercise to the interested reader unless requested.