一个简单的SHELL在UNIX系统下创建进程和管理进程

1、设计一：设计任务：实现一个简单的shell（命令行解释器），类似于bash, csh等。本设计的主要目的在于学会如何在Unix系统下创建进程和管理进程。要求实现的shell支持以下内部命令：1. cd <目录>更改当前的工作目录到另一个<目录>。如果<目录>未指定，输出当前工作目录。如果<目录>不存在，要求有适当的错误信息提示。改命令应能够改变PWD的环境变量。2. environ 列出所有环境变量字符串的设置（类似于Unix系统下的env命令）。3. echo <内容>显示echo后的内容且换行。4. help 简短概要地输出你的s

2、hell的使用方法和基本功能。5. jobs输出shell当前的一系列子进程，要求提供子进程的命名和PID号。6. quit, exit, bye退出shell。所有的内部命令应当优于在$PATH中同名的程序。任何非内部命令必须请求shell创建一个新进程，且该子进程执行指定的程序。这个新进程必须继承shell的环境变量和指定的命令行参数。要求实现的shell支持以下内部命令：1. Batch Processing 如果shell启动带有一个文件名作为参数，打开该文件并执行文件里所有命令。待所有进程全部结束退出shell。2. Debugging 提供-v选项，shell启动时打开此选项将在运

3、行过程中输出若干调试信息。在该模式下，shell应该显示所有被创建了的进程的PID号，通报已结束的子进程和传递给子进程的参数等。3. Prompt (命令行提示符) 解释器打印$PS2作为提示符。4. Background Processing 如果命令以符合&终止，在后台并发执行该程序。Shell立即等待下一命令的输入，而不等待该程序的结束。注：所有命令和参数由空格或tab符分隔。实验代码#include <string.h>#include <stdlib.h>#include <conio.h>#include <stdio.h>#

4、include <dir.h>#include <dos.h>#include <time.h>/*定义全局变量*/char root_dir3;char pre_dir255;char *cmd_line255;char curuser10;struct userinf char username10; char userpass10;/*函数申明*/void init();int login();int getcmd();void dir();void cd();void clear();void newdir();void deldir();void

5、del();void copy();void cut();void account();void help();main() init(); while(1)/* 消息循环 */ switch(getcmd() case 0: help(); break; case 1: dir(); break; case 2: cd(); break; case 3: newdir(); break; case 4: deldir(); break; case 5: del(); break; case 6: copy(); break; case 7: cut(); break; case 8: acc

6、ount(); break; void init()/* 程序初始化 */ if(login()=0) exit(0); strcpy(pre_dir,"C:");/*设定当前目录*/ clear();/* 清屏 */ printf("S Shell-Above Windows XP Ver 1.0n"); printf("(C) Copyright 2007 stars_625.nn"); getchar();/* 清空缓冲区 */int login()/* 程序登陆 */ char name10; char pass10; int

7、 logintime=3; FILE *fp; struct userinf inf; while(logintime>0)/* 登陆错误超过三次自动退出 */ printf("Login:"); scanf("%s",name); printf("Password:"); scanf("%s",pass); if(fp=fopen("inf.dll","r")=NULL) printf("Can't open inf.dll file!n"

8、); printf("Press any key to exit."); getch(); exit(0); while(fread(&inf,sizeof(inf),1,fp)=1 && strcmp(inf.username,name)!=0) fclose(fp); if(strcmp(inf.username,name)=0) if(strcmp(inf.userpass,pass)=0) strcpy(curuser,inf.username); clear(); return 1; else printf("Login erro

9、r, Press any key to relogin!n"); getch(); clear(); else printf("The user is not exist, Press any key to relogin!n"); getch(); clear(); logintime-; printf("Login error above three times, Press any key to exit!"); getch(); return 0;int getcmd()/* 获得命令 */ int i=0,j=0,k=0; char

10、buf255; printf("%s>",pre_dir);/* 打印提示符 */ fgets(buf, 255, stdin); cmd_linej = calloc(255, sizeof(char); while (bufi != 'n' && bufi != '0')/* 命令分析 */ if (bufi != ' ') cmd_linejk = bufi; +k; else cmd_linej + 1 = calloc(255, sizeof(char); k = 0; +j; +i; cmd_

11、linej + 1=0; if(strcmp(cmd_line0,"exit")=0) exit(0); else if(strcmp(cmd_line0,"/?")=0 | strcmp(cmd_line1,"/?")=0) return 0; else if(strcmp(cmd_line0,"dir")=0) return 1; else if(strcmp(cmd_line0,"cd")=0) return 2; else if(strcmp(cmd_line0,"newdir

12、")=0) return 3; else if(strcmp(cmd_line0,"deldir")=0) return 4; else if(strcmp(cmd_line0,"del")=0) return 5; else if(strcmp(cmd_line0,"copy")=0) return 6; else if(strcmp(cmd_line0,"cut")=0) return 7; else if(strcmp(cmd_line0,"account")=0) return

13、 8; else if(cmd_line01=':') strcpy(pre_dir,cmd_line0); strcat(pre_dir,""); else if(strcmp(cmd_line0,"clear")=0) clear(); else printf("The command is not supported!n"); void dir()/* 列出文件及文件夹 */ struct ffblk ff; char filepath255; strcpy(filepath,pre_dir); findfirs

14、t(strcat(filepath,"*.*"),&ff,FA_DIREC); if(ff.ff_attrib=16) printf("<DIR>t"); else printf(" t"); printf("%sn",ff.ff_name); while(findnext(&ff)=0) if(ff.ff_attrib=16) printf("<DIR>t"); else printf(" t"); printf("%sn&

15、quot;,ff.ff_name); void cd()/* 改变当前目录 */ int i=0; struct ffblk ff; char filepath255; strcpy(filepath,pre_dir); if(strcmp(cmd_line1,".")=0)/* 返回上一层目录 */ while(filepathi!='0') i+; if(filepathi-2!=':') i=i-2; while(filepathi!='' && i>=2) i-; filepathi+1='

16、;0' strcpy(pre_dir,filepath); else if(strcmp(cmd_line1,"")=0)/*返回根目录*/ while(filepathi!='') i+; filepathi+1='0' strcpy(pre_dir,filepath); else findfirst(strcat(filepath,"*.*"),&ff,FA_DIREC); while(strcmp(ff.ff_name,cmd_line1)!=0) if(findnext(&ff)!=0) b

17、reak; if(strcmp(ff.ff_name,cmd_line1)=0) strcat(pre_dir,cmd_line1); strcat(pre_dir,""); else printf("Can't find the file!n"); void clear() clrscr();void newdir() char filepath255; strcpy(filepath,pre_dir); if(mkdir(strcat(filepath,cmd_line1)=0) printf("Make dir '%s&#

18、39; successfully!n",cmd_line1); else printf("Make dir error!n"); void deldir() char filepath255; strcpy(filepath,pre_dir); if(rmdir(strcat(filepath,cmd_line1)=0) printf("Delete dir '%s' successfully!n",cmd_line1); else printf("Delete dir error!n"); void del

19、() char filepath255; strcpy(filepath,pre_dir); if(unlink(strcat(filepath,cmd_line1)=0) printf("Delete %s successfully!n",cmd_line1); else printf("Delete error!n"); void copy() char filepath255; char sourcepath255; char aimpath255; FILE *newfp; FILE *oldfp; char ch; strcpy(filepat

20、h,pre_dir); if(cmd_line11!=':') strcpy(sourcepath,filepath); strcat(sourcepath,cmd_line1); else strcpy(sourcepath,cmd_line1); if(cmd_line21!=':') strcpy(aimpath,filepath); strcat(aimpath,cmd_line2); else strcpy(aimpath,cmd_line2); if(oldfp=fopen(sourcepath,"r")=NULL) printf

21、("Can't open old file!n"); if(newfp=fopen(aimpath,"w")=NULL) printf("Can't creat new file!n"); while(ch=fgetc(oldfp)!=EOF) fputc(ch,newfp); fclose(oldfp); fclose(newfp); printf("Copy from %s to %s successfully!n",sourcepath,aimpath);void cut() char fil

22、epath255; char sourcepath255; char aimpath255; FILE *newfp; FILE *oldfp; char ch; strcpy(filepath,pre_dir); if(cmd_line11!=':') strcpy(sourcepath,filepath); strcat(sourcepath,cmd_line1); else strcpy(sourcepath,cmd_line1); if(cmd_line21!=':') strcpy(aimpath,filepath); strcat(aimpath,c

23、md_line2); else strcpy(aimpath,cmd_line2); if(oldfp=fopen(sourcepath,"r")=NULL) printf("Can't open old file!n"); if(newfp=fopen(aimpath,"w")=NULL) printf("Can't creat new file!n"); while(ch=fgetc(oldfp)!=EOF) fputc(ch,newfp); fclose(oldfp); fclose(newf

24、p); if(unlink(sourcepath)=0) printf("Cut from %s to %s successfully!n",sourcepath,aimpath); else printf("Delete old file error!n"); void account() FILE *fp; struct userinf inf; if(strcmp(cmd_line1,"/add")=0) if(fp=fopen("inf.dll","r+")=NULL) printf(&

25、quot;Can't open inf.dll file!n"); printf("Press any key to exit."); getch(); while(fread(&inf,sizeof(inf),1,fp)=1 && strcmp(inf.username,cmd_line2)!=0) if(strcmp(inf.username,cmd_line2)=0) printf("Create user error, the user is exist!n"); else strcpy(inf.user

26、name,cmd_line2); strcpy(inf.userpass,cmd_line3); if(fwrite(&inf,sizeof(inf),1,fp)=1) printf("Create user %s successfully!n",inf.username); else printf("Create user error!n"); fclose(fp); else if(strcmp(cmd_line1,"/edit")=0) if(fp=fopen("inf.dll","r+&q

27、uot;)=NULL) printf("Can't open inf.dll file!n"); printf("Press any key to exit."); getch(); while(fread(&inf,sizeof(inf),1,fp)=1 && strcmp(inf.username,cmd_line2)!=0) if(strcmp(inf.username,cmd_line2)!=0) printf("Edit user error, the user is not exist!n"

28、); else strcpy(inf.username,cmd_line2); strcpy(inf.userpass,cmd_line3); fseek(fp,-20L,1); if(fwrite(&inf,sizeof(inf),1,fp)=1) printf("Edit user %s successfully!n",inf.username); else printf("Edit user error!n"); fclose(fp); else printf("Please enter correct parameter,typ

29、e /? for help!n"); void help() if(strcmp(cmd_line0,"/?")=0) printf("The list of commands.nn"); printf(" dirttList the files and dirs.n"); printf(" cdttChange the dir.n"); printf(" clearttClear the screen.n"); printf(" newdirtMake a dir.n&qu

30、ot;); printf(" deldirtDelete a dir.n"); printf(" delttDelete a file.n"); printf(" copyttCopy a file from a place to another.n"); printf(" cutttCut a file from a place to another.n"); printf(" accounttAdd edit or delete a account.nn"); printf("Fo

31、r more information add type /? after command.nn"); printf("Notice:All the command line is capitalization distinction!nn"); else if(strcmp(cmd_line0,"dir")=0) printf("List the files and dirs.nn"); printf("dir pathnn"); printf(" pathttThe dir you want

32、to list.n"); printf(" ttif path is NULL then list the current dir.nn"); else if(strcmp(cmd_line0,"cd")=0) printf("Change the dir.nn"); printf("cd < | . | path>nn"); printf(" ttReturn to the root dir.n"); printf(" .ttReturn to the pare

33、nt dir.n"); printf(" pathttThe dir you want change to.nn"); else if(strcmp(cmd_line0,"clear")=0) printf("Clear the screen.nn"); printf("clearnn"); else if(strcmp(cmd_line0,"newdir")=0) printf("Make a dir.nn"); printf("newdir pathnn"); printf(" pathttThe dir path which you want to create.nn"); else if(strcmp(cmd_line0,"deldir")=0) printf("Delete a dir.nn"); printf("deldir pathnn"); printf(" pathttThe dir path which you want to delete.nn"); else if(strcmp(cmd_line0,&