if

if

 

condition

1 

then

 

commands1

  [ 

elif

 

condition2

 	

then

 

commands2

 ]  .  .  . [ 

else

 

commands3

 ] 

fi

If condition1 is met, do commands1 ; otherwise, if condition2 is met, do commands2 ; if neither is met, do commands3 . Conditions are usually specified with the test command. See additional examples under : and exit .

Examples

Insert a 0 before numbers less than 10:

if [ $counter -lt 10 ] then number=0$counter else number=$counter fi

Make a directory if it doesn't exist:

if [ ! -d $dir ]; then    mkdir $dir    chmod 775 $dir fi