---
name: "concat"
section: "n"
platform: "macos"
package: "tcl"
version: "152"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/concat/n"
---

# concat(n)

Join lists together

## NAME

concat - Join lists together

## SYNOPSIS

**concat** ?*arg arg ...*?

## DESCRIPTION

This command joins each of its arguments together with spaces after trimming leading and trailing white-space from each of them.  If all the arguments are lists, this has the same effect as concatenating them into a single list. It permits any number of arguments; if no *arg*s are supplied, the result is an empty string.

## EXAMPLES

Although **concat** will concatenate lists, flattening them in the process (so giving the following interactive session):

*%* **concat** a b {c d e} {f {g h}} *a b c d e f {g h}*

it will also concatenate things that are not lists, as can be seen from this session:

*%* **concat** " a b {c   " d "  e} f" *a b {c d e} f*

Note also that the concatenation does not remove spaces from the middle of values, as can be seen here:

*%* **concat** "a   b   c" { d e f } *a   b   c d e f*

(i.e., there are three spaces between each of the **a**, the **b** and the **c**).

## SEE ALSO

[append(n)](/append/n.md), [eval(n)](/eval/n.md), [join(n)](/join/n.md)

## KEYWORDS

concatenate, join, lists