(完整word版)linux下ls命令的C语言实现(实现大部分功能).doc

Readme:将两个文件list.h和ls.c文件放入linux下同一目录下，gcc编译，之后就可以通过./可执行文件名-选项参数运行了。本程序实现大部分ls的功能，在ubuntu16.04下测试可用，大家有什么不懂的欢迎探讨。qq:280438369
List.h文件代码内容如下：
#ifndef_LINUX_LIST_H
#define_LINUX_LIST_H

/*
*Simpledoublylinkedlistimplementation.
*
*Someoftheinternalfunctions("__xxx")areusefulwhen
*manipulatingwholelistsratherthansingleentries,as
*sometimeswealreadyknowthenext/preventriesandwecan
*generatebettercodebyusingthemdirectlyratherthan
*usingthegenericsingle-entryroutines.
*/

structlist_head{
structlist_head*next,*prev;
};

#defineLIST_HEAD_INIT(name){&(name),&(name)}

#defineLIST_HEAD(name)\
structlist_headname=LIST_HEAD_INIT(name)

#defineINIT_LIST_HEAD(ptr)do{\
(ptr)->next=(ptr);(ptr)->prev=(ptr);\
}while(0)

/*
*Insertanewentrybetweentwoknownconsecutiveentries.
*
*Thisisonlyforinternallistmanipulationwhereweknow
*theprev/nextentriesalready!
*/
static__inline__void__list_add(structlist_head*new,
structlist_head*prev,
structlist_head*next)
{
next->prev=new;
new->next=next;
new->prev=prev;
prev->next=new;
}

/**
*list_add-addanewentry
*@new:newentrytobeadded
*@head:listheadtoadditafter
*
*Insertanewentryafterthespecifiedhead.
*Thisisgoodforimplementingstacks.
*/
static__inline__voidlist_add(structlist_head*new,structlist_head*head)
{
__list_add(new,head,head->next);
}

/**
*list_add_tail-addanewentry
*@new:newentrytobeadded
*@head:listheadtoadditbefore
*
*Insertanewentrybeforethespecifiedhead.
*Thisisusefulforimplementingqueues.
*/
static__inline__voidlist_add_tail(structlist_head*new,structlist_head*head)
{
__list_add(new,head->prev,head);
}

/*
*Deletealistentrybymakingtheprev/nextentries
*pointtoeachother.
*
*Thisisonlyforinternallistmanipulationwhereweknow
*theprev/nextentriesalready!
*/
static__inline__void__list_del(structlist_head*prev,
structlist_head*next)
{
next->prev=prev;
prev->next=next;
}

/**
*list_del-deletesentryfromlist.
*@entry:theelementtodeletefromthelist.
*Note:list_emptyonentrydoesnotreturntrueafterthis,theentryisinanundefinedstate.