echo string and variable bash code example

Example 1: combine strings bash

foo="Hello"
foo="${foo} World"
echo "${foo}"
> Hello World

Example 2: echo variable bash

echo "${var}"

Example 3: bash echo in variable

#Just use following structure to store output of command into a variable:
var=$(command)
#For example:
var=$(echo 'hi')	#store hi into var
var=$(ls)	#store list of files into var

Example 4: bash store string in variable

${!var}	#Just use to use reference value inside another variable ;)