For more information on how operators work, consult the perlop documentation bundled with Perl. A.11.1 Arithmetic OperatorsPerl has the basic five arithmetic operators:
These operators work on both integers and floating-point values (and if you're not careful, strings as well). Perl also has a modulus operator, which computes the remainder of two integers: % modulus For example, 17 % 3 is 2, because 2 is left over when you divide 3 into 17. Perl also has autoincrement and autodecrement operators: ++ add one -- subtract one Unlike the previous six operators, these change a variable's value. $x++ adds one to $x , changing 4 to 5 (or a to b). A.11.2 Bitwise OperatorsAll scalars, whether numbers or strings, are represented as sequences of individual bits "under the hood." Every once in a while, you need to manipulate those bits, and Perl provides five operators to help:
A.11.3 String OperatorsTwo strings may be concatenated , i.e., joined end to end, with the dot operator: 'This is a ' . 'joined string' This results in the value ' This is a joined string '. A string may be repeated with the x operator: print "Hear ye! " x 3; This prints: Hear ye! Hear ye! Hear ye! A.11.4 File Test OperatorsFile test operators are unary operators that test files for certain characteristics, such as -e $file , which returns true if the file $file exists. Table A-2 lists some available file test operators. Table A-2. File test operators
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