---
name: "append"
section: "n"
platform: "linux"
package: "tcl"
version: "8.6.16-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/append/n"
---

# append(n)

Append to variable

```

```

## NAME

append - Append to variable

## SYNOPSIS

**append** *varName* ?*value value value ...*?

```

```

## DESCRIPTION

Append all of the *value* arguments to the current value of variable *varName*.  If *varName* does not exist, it is given a value equal to the concatenation of all the *value* arguments. The result of this command is the new value stored in variable *varName*. This command provides an efficient way to build up long variables incrementally. For example, “**append a $b**” is much more efficient than “**set a $a$b**” if **$a** is long.

## EXAMPLE

Building a string of comma-separated numbers piecemeal using a loop.

```
set var 0
for {set i 1} {$i<=10} {incr i} {
    append var "," $i
}
puts $var
# Prints 0,1,2,3,4,5,6,7,8,9,10
```

## SEE ALSO

[concat(n)](/concat/n.md), [lappend(n)](/lappend/n.md)

## KEYWORDS

append, variable