If Statements

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If statements test conditions and execute commands when the condition is true. The if statement has the following general format:

 if [ condition ]   then      commands elif [ condition ]   then      commands else      commands fi 

The if statements begins with if and ends with fi (if spelled backward). All three parts are not required. Only the if section is required. The elif (elseif) and the else sections are optional. Also, notice that the if section and the elif section start with then, but the else section does not. You can use more than one elif section, but only one if and else section is allowed. An if statement can be as simple as:

 if [ $x -eq 1 ]   then     echo Hello fi 

A more complex statement is:

 if [ $day = "Saturday" -o $day = "Sunday" ]   then      echo Sleep in elif [ $day = "Monday" ]   then      echo Call in sick else      echo Go to work fi 

You can nest if statements inside of if statements, as follows:

 if [ $city = "Miami" ]   then   if [ $name = "John" ]       then         echo Hello John in Miami   else         echo Hello friend in Miami    fi fi 

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    Spring Into Linux
    Spring Into Linux
    ISBN: 0131853546
    EAN: 2147483647
    Year: 2005
    Pages: 362
    Authors: Janet Valade

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