subst

Perform backslash, command, and variable substitutions 

Tcl Built-In Commands

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}.

PORTABILITY

Windows 10. Windows Server 2016. Windows Server 2019. Windows 11. Windows Server 2022. Windows Server 2025.

AVAILABILITY

PTC MKS Toolkit for Power Users
PTC MKS Toolkit for System Administrators
PTC MKS Toolkit for Developers
PTC MKS Toolkit for Interoperability
PTC MKS Toolkit for Professional Developers
PTC MKS Toolkit for Enterprise Developers
PTC MKS Toolkit for Enterprise Developers 64-Bit Edition

PTC MKS Toolkit 10.5 Documentation Build 40.