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The Linux Command Line

Cover of The Linux Command Line by William E. Shotts Jr. Published by No Starch Press
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Arithmetic Evaluation and Expansion

We looked at arithmetic expansion in Chapter 7. It is used to perform various arithmetic operations on integers. Its basic form is


where expression is a valid arithmetic expression.

This is related to the compound command (( )) used for arithmetic evaluation (truth tests) we encountered in Chapter 27.

In previous chapters, we saw some of the common types of expressions and operators. Here, we will look at a more complete list.

Number Bases

Back in Chapter 9, we got a look at octal (base 8) and hexadecimal (base 16) numbers. In arithmetic expressions, the shell supports integer constants in any base. Table 34-1 shows the notations used to specify the bases.

Table 34-1. Specifying Different Number Bases ...

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