Assiging a number to a module - bash

Question

I need to be able to assign a number to a module, my current code is below. Gap is where it needs to be assigned.
assignmodules(){
#Assign first module
x=1
modules=$(ls ./modules)
for module in modules; do
echo "$module assigned to slot $x"
x=$(x+1)
done
}
A few things:
Module title has to be printed in a different function, so i cant print it within the for loop.
Module needs to be run this way:
case $choice in
1) module1
2) module2
3) module3
etc.
Needs to be printed as following (If i find a good a solution that doesn't do it right, ill probably still use that.):
[1] Module1 [2] Module2
[3] Module3 [4] Module4
etc.
I tried this in the blank:
[{x}]module=$module
(i don't think this is exactly what i tried, i believe it was slightly different but i cant remember)
I wanted it to do as described above, but i don't think it will.

Answer 1

If you're using Bash, just use an array and some globbing and special parameter expansion.
assignmodules() {
set -- ./modules/*
modules=(0 "${#/#./modules/}")
unset 'modules[0]'
declare -p modules # Optionally show result
}
Somewhere you can print the modules list using
for i in "${!modules[#]}"; do
echo "[$i] ${modules[i]}"
done
Or
for i in "${!modules[#]}"; do
echo -n "[$i] ${modules[i]} "
(( i % 2 == 0 )) && echo
done
(( i % 2 )) && echo
It's also recommended to add shopt -s nullglob at the beginning of the script, especially if
modules directory can sometimes be empty.
Lastly, if you're wanting to ask user for choices, look at the select command. You may not need to display them manually. Run help select.

Answer 2

Just put your modules in an array: Numerically-indexed arrays (the default kind) have indices that are numbered by nature (note that these numbers start at 0, not 1).
assignmodules() {
declare -ga modules # explicitly declare global array (optional)
modules=( modules/* ) # put all modules directory entries in an array
modules=( "${modules[#]#*/}" ) # strip modules/ prefix off each entry
}
assignmodules # calling that function leaves modules assigned
# to print your list of modules in the specific format requested might look like:
print_args=( ) # generate format string argument array
for modules_idx in "${!modules[#]}"; do # iterate over indices in array
module=${modules[$module_idx]} # retrieve corresponding module name
print_args+=( "[$module_idx]" "$module" ) # append to list of stuff to print
done
# format string is repeated until all arguments are consumed
# so this way we get two columns as you requested
printf '%s %s\t%s %s\n' "${print_args[#]}" # actually print our list