osx man page for concat

concat(n)						       Tcl Built-In Commands							 concat(n)

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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, 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), eval(n), join(n)

KEYWORDS
       concatenate, join, lists

Tcl									8.3								 concat(n)