iTP Secure WebServer System Administrator's Guide (iTPWebSvr 5.1+)

Tool Command Language (Tcl) Basics

iTP Secure WebServer System Administrator’s Guide—522659-001

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Tcl Commands

This section describes Tcl commands in general and then discusses specific Tcl

commands commonly used in configuration scripts.

A Tcl command consists of a command procedure (keyword) followed by zero or more

arguments. For example:

puts stdout "Hello world!" ; exit

In this example, puts is a command procedure with two arguments: stdout and the

string Hello world! It writes Hello world! to standard output. The second

procedure, exit, has no arguments; it simply causes the Tcl script to terminate.

Tcl commands can take five different kinds of arguments:

•

Numeric

Numeric arguments consist of either integers or floating-point numbers. Tcl

command procedures expect number-valued arguments to be a single value (for

example, 13 or 1.34). Expressions can be used in arguments if they are evaluated by

the Tcl command procedure expr, which returns a single value. For example:

set my_num [expr 2*3]

Tcl provides the same arithmetic, logical, bit-wise, and relational operators, as well

as math functions, used in the C language. The one exception is that the relational

operators are also used on string values for comparison.

•

String

String arguments consist of sequences of ASCII characters, including spaces. For

example:

"Access Denied!"

Note the required use of quotes.

•

List

List arguments consist of zero or more elements separated by spaces. For example:

"*.status.com *.money.com *.power.com"

Note the required use of quotes.