CODEWITHSUNDEEP
bashvariables
Pol Hallen
Pol Hallen

Reputation: 1872

substitution of variables with input command

#!/bin/sh

own1="jack"
own2="mark"
own3="black"
    read n "insert number [1-3]"
    echo $own{n}

the purpose is substitution own[1-3] variable with new n variable

Upvotes: 0

Views: 45

Answers (1)

glenn jackman
glenn jackman

Reputation: 247210

You'd use an indirect variable (documented in the 4th paragraph of Shell Parameter Expansion)

varname="own$n"
echo "${!varname}"

Or in bash version 4.3+, use a nameref

declare -n name="own$n"
echo "$name"

But this is much easier with arrays:

own=(jack mark black)              # an array with 3 elements
read -p "insert number [1-3] " n   # use `-p` option to set the prompt

# TODO validate n is actually a number in the correct range

# bash arrays are zero-indexed, so
echo "${own[n - 1]}"

For elememnts of a numerically indexed array, the index is an arithmetic expression.

However, to ask the user to select one of a number of options, use the select command:

own=(jack mark black)
PS3="Choose a name: "
select name in "${own[@]}"; do
  [[ -n $name ]] && break
done
echo "you chose $name"

Upvotes: 2

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