Concat strings in a shell script [duplicate]

Answer 1

How about this:

var="${var}string"

Answer 2

It depends on the shell, but since question was tagged bash:

var='my'
var=$var'string'

Answer 3

No. For various reasons.

# most sh-compatible shells
var="my"
var="$var string"

# advanced shells
var="my"
var+=" string"