if

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.