Linux in a Nutshell, Third Edition

Name

if

Synopsis

if ( condition )

    command1

[else

    command2]

Description

If condition is true, do command1; otherwise, do command2. Condition can be an expression using any of the relational operators <, <=, ==, !=, >=, or >, as well as the pattern-matching operator ~. A series of commands must be put within braces.

Example

The following lines determine whether the first word in each line starts with A, uppercase or lowercase:

if ($1 ~ /[Aa]*/)
    ...Begins with A or a