shell->一个经典的shell脚本结构

　　shell脚本类常用的条件分支判断是if，case。但是也可以用其他的方式来实现，如下脚本文件名字为mfc。其中每一个独立的函数都是一个分支，函数上的注释即是该函数的说明信息。

#!/bin/sh

# fun1:   note: the first test function
# fun1: usage1: mfc fun1
fun1()
{
    echo "inner function"
}

# fun2:   note: the second test function
# fun2: usage1: mfc fun2 arg1 arg2
fun2()
{
    echo "function: $1 $2 $3 $4"
}

_debug_()
{
    echo "inner function"
}

# help: Give 'mfc help <function>' for more details.
help ()
{
    [ -z "$2" ] && {
        echo "Usage: mfc <function> [args1...n]"
        echo "Available functions:-"
        cat $0 | grep () | cut -d'(' -f1 |grep -v "_*_" | awk '{ print "	"$1 }'
        echo "Give 'mfc help <function>' for more details."
    } || {
        cat $0 | grep -w $2: | cut -d':' -f2-
    }
}

[ -n "$1" ] && {
    name="$1"
    shift
    $name $name $@ || >&-
} || help

执行效果如下：

# ./mfc 
Usage: mfc <function> [args1...n]
Available functions:-
        fun1
        fun2
        help
Give 'mfc help <function>' for more details.
# ./mfc help
Usage: mfc <function> [args1...n]
Available functions:-
        fun1
        fun2
        help
Give 'mfc help <function>' for more details.
# ./mfc help fun1
   note: the first test function
 usage1: mfc fun1
# ./mfc help fun2
   note: the second test function
 usage1: mfc fun2 arg1 arg2
# ./mfc fun1
inner function
# ./mfc fun2 param1 param2 param3
function: fun2 param1 param2 param3
#