subst(3Tcl)

NAME
     subst - Perform backslash, command, and variable substitutions

SYNOPSIS
     subst ?-nobackslashes? ?-nocommands? ?-novariables? string


DESCRIPTION
     This command performs variable substitutions, command substitutions, and
     backslash substitutions on its string argument and returns the fully-
     substituted result.  The substitutions are performed in exactly the same
     way as for Tcl commands.  As a result, the string argument is actually
     substituted twice, once by the Tcl parser in the usual fashion for Tcl
     commands, and again by the subst command.

     If any of the -nobackslashes, -nocommands, or -novariables are specified,
     then the corresponding substitutions are not performed.  For example, if
     -nocommands is specified, no command substitution is performed:  open and
     close brackets are treated as ordinary characters with no special
     interpretation.

     Note: when it performs its substitutions, subst does not give any special
     treatment to double quotes or curly braces.  For example, the script

          set a 44
          subst {xyz {$a}}

     returns ``xyz {44}'', not ``xyz {$a}''.


KEYWORDS
     backslash substitution, command substitution, variable substitution