if
(
condition
)
command
[
else
]
[
command
]
If
condition
is true, do
command(s)
, otherwise do
command
in
else
clause. Condition can be an expression using
any of the relational operators <, <=, ==, !=, >=, or >, as well as
the pattern-matching operator
~
(e.g., "
if ($1 ~ /[
Aa
].*/)").
A series of commands must be put within braces.