Provided by: tcl8.4-doc_8.4.20-7_all 

NAME
concat - Join lists together
SYNOPSIS
concat ?arg arg ...?
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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 args are supplied, the result is an empty
string.
EXAMPLES
Although concat will concatenate lists (so the command:
concat a b {c d e} {f {g h}}
will return "a b c d e f {g h}" as its result), it will also concatenate things that are not lists, and
hence the command:
concat " a b {c " d " e} f"
will return "a b {c d e} f" as its result.
Note that the concatenation does not remove spaces from the middle of its arguments, so the command:
concat "a b c" { d e f }
will return "a b c d e f" (i.e. with three spaces between the a, the b and the c).
SEE ALSO
append(3tcl), eval(3tcl)
KEYWORDS
concatenate, join, lists
Tcl 8.3 concat(3tcl)