8.1. Operators (Revision #2)

assignment

variable assignment

Initializing or changing the value of a variable

=

All-purpose assignment operator, which works for both arithmetic and string assignments.

var=27
category=minerals  # No spaces allowed after the "=".

    Do not confuse the "=" assignment operator with the = test operator.

#   =  as a test operator

if [ "$string1" = "$string2" ]
then
   command
fi

#  if [ "X$string1" = "X$string2" ] is safer,
#+ to prevent an error message should one of the variables be empty.
#  (The prepended "X" characters cancel out.)

arithmetic operators

+

plus

-

minus

*

multiplication

/

division

**

exponentiation