[string map {at @ x . ext .com} [append _ sigzero "at" gmail ext]]

 #!/bin/sh
 # The next line is executed by /bin/sh, but not tcl \
 exec tclsh "$0" ${1+"$@"} 

 # 1 issue -- There will be a blank line at the top and bottom
 # 2 issue -- The type quoting used with a Perl heredoc determines variable interpolation

 set v1 [exec whoami]
 set v2 [exec date]

 set msg "
 This will be a long multi-line message. 
 
 The variables \$v1 and \$v2 will interpolate in here as well.

 This is who I am logged in as:  $v1

 This is the date:  $v2
 "

 puts $msg