cat

cat — Concatenates any number of variables or strings fed into it.

Two or more strings that will be merged into one.
Examples: 

    if $name equal to "Hello"
    {$name|cat:' World!'}

The above example will output:

Hello World

    if $name equal to "Psychics predict world didn't end"
    {$name|cat:' yesterday':' but any other day'}

The above example will output:

Psychics predict world didn't end yesterday but any other day
{"When will you come— "|cat:' tomorrow':' or':' some':' other day?'}

The above example will output:

When will you come—tomorrow or some other day?