06 分支

6.1 if语句的帮助

[root@centos74 Bash]$ help if
if: if COMMANDS; then COMMANDS; [ elif COMMANDS; then COMMANDS; ]... [ else COMMANDS; ] fi

6.2 简单的if语句

#!/bin/bash
score=65
if [ "$score" -gt 60 ] ; then
    echo "$score >60"
fi

6.3 正常的if语句

#!/bin/bash
score=65
if [ "$score" -gt 60 ] ; then
    echo "$score >60"
else
    echo "$score <=60"
fi

6.3 复杂的if语句

#!/bin/bash
score=41
if [ "$score" -gt 60 ] ; then
    echo "$score >60"
elif [ "$score" -gt 40 ] ; then
    echo "$score <=60 , $score >40"
else
    echo "$score <=40"
fi

6.4 嵌套的if语句

#!/bin/bash
score=41
if [ "$score" -gt 60 ] ; then
    echo "$score >60"
else
    if [ "$score" -gt 40 ] ; then
        echo "$score <=60 , $score >40"
    else
        echo "$score <=40"
    fi
fi