Expansion

[me@linuxbox ~]$ echo $(((5**2) * 3))

Here is an example using the division and remainder operators. Notice the effect of inte-

ger division:

[me@linuxbox ~]$ echo Five divided by two equals $((5/2))

Five divided by two equals 2

[me@linuxbox ~]$ echo with $((5%2)) left over.

with 1 left over.

Arithmetic expansion is covered in greater detail in Chapter 34.

Brace Expansion

Perhaps the strangest expansion is called brace expansion. With it, you can create multi-

ple text strings from a pattern containing braces. Here's an example:

[me@linuxbox ~]$ echo Front-{A,B,C}-Back

Front-A-Back Front-B-Back Front-C-Back

Patterns to be brace expanded may contain a leading portion called a preamble and a

trailing portion called a postscript. The brace expression itself may contain either a

comma-separated list of strings, or a range of integers or single characters. The pattern

may not contain embedded whitespace. Here is an example using a range of integers:

[me@linuxbox ~]$ echo Number_{1..5}

Number_1 Number_2 Number_3 Number_4 Number_5

Integers may also be zero-padded like so:

[me@linuxbox ~]$ echo {01..15}

01 02 03 04 05 06 07 08 09 10 11 12 13 14 15

[me@linuxbox ~]$ echo {001..15}

001 002 003 004 005 006 007 008 009 010 011 012 013 014 015

A range of letters in reverse order: