Built-In Commands - incr manual page

### NAME

incr - Increment the value of a variable

### SYNOPSIS

incr varName ?increment?

### DESCRIPTION

Increments the value stored in the variable whose name is varName. The value of the variable must be an integer. If increment is supplied then its value (which must be an integer) is added to the value of variable varName; otherwise 1 is added to varName. The new value is stored as a decimal string in variable varName and also returned as result.

### EXAMPLES

Add one to the contents of the variable x:

    incr x

Add 42 to the contents of the variable x:

    incr x 42

Add the contents of the variable y to the contents of the variable x:

    incr x $y

Add nothing at all to the variable x (often useful for checking whether an argument to a procedure is actually numeric and generating an error if it is not):

    incr x 0

### SEE ALSO

expr

### KEYWORDS

add, increment, variable, value

    Copyright © 1993 The Regents of the University of California.
    Copyright © 1994-1996 Sun Microsystems, Inc.
    Copyright © 1995-1997 Roger E. Critchlow Jr.