Shell parameter passing

$# 是传给脚本的参数个数$0是脚本本身的名字$1 是传递给该shell脚本的第一个参数$2是传递给该shell脚本的第二个参数[email protected] 是传给脚本的所有参数的列表$* 是以一个单字符串显示所有向脚本传递的参数，与位置变量不同，参数可超过9个$$ 是脚本运行的当前进程ID号$? 是显示最后命令的退出状态，0表示没有错误，其他表示有错误

Difference:@*

• Same point: All parameters are referenced
• Different points: only in double quotes. Suppose that three parameters were written when the script was run (stored in123) then " * "Equivalent to"123"（Mass transferHandedThe one Ginseng number ) ;" @ "equivalent to" 1""2 "" $ $ "(three parameters passed)

A daemon script demon:

#################### VERSION=0.0.4####################!/bin/bash################################## #Global parameters######################################## #set-X #EchoOncur_dir=`pwd' Va_log_level="Err"Va_run_level="Demon"#### forRecordfiledeletedefault_days= theRecord_file_path=/var/Video_recorddefault_file_check=1##### Unit:gdefault_mini_space= theProcess_num=2#CertMS #darwinstreamingserver#certms_server#darwin_server#functions#################### #parse argument#### ############## #usage () {Echo "######################################"  Echo "usage of maintain.sh:"  Echo "Options"  Echo "-l:videomon log level [Warn, info, err], default is Err"  Echo "-m:videomon run Mod[demon, foreground], default is Demon"  Echo "-c:record File Delete check! [0:not check 1:check, default is 1]"  Echo "-N: [Delete The record files of the The N days ago, default is ~ Days]"  Echo "-D: [Record file path, default is:/var/video_record]"  Echo "For example:./maintain.sh-l info-m foreground-c 1-n 10-d/video_record or./maintain.sh"  Echo "-? : Usage Info"    Echo "######################################"}get_opt () { whileGetopts":? l:m:c:n:d:"optname Do     Case "$optname" inch    "L") Va_log_level=$OPTARG;; "m") Va_run_level=$OPTARG;; "C") Default_file_check=$OPTARG;; "N") Default_days=$OPTARG;; "D") Record_file_path=$OPTARG;; "?") Usage Exit0      ;; *) # should not occurEcho "maintain.sh:Unknown Error while processing options"Exit0      ;; Esac Done}##################### #Video_Monitor clean################### #video_monitor_clean () { for((i =0; $i < Process_num; i++ ));  Do        Echo$i; Pid_videomon=`PSAux|grep-Vgrep|grep  "videomon$i"|grep "$"|sed-N'1P'|awk '{print $}'`        if[$pid _videomon] Then            Killall-9videomon$ifi     Done}##################### #ran_videomon_monitor ################### #ran_videomon_monitor () {Echo$1CD $CUR _dir/bin$1  if[$VA _run_level = ="Demon" ]   Thennohup./videomon$1-L $VA _log_level-p pid-d &Elsenohup./videomon$1-L $VA _log_level-p PID &fi  EchoStart Videomon success!}##################### #recordfilecheck################### #record_file_check () {CD $CUR _dirif[-F Record_file_delete.SH ]   Then    chmod+x Record_file_delete.SH# # Pid_record_sh=`PSAux|grep-Vgrep|grep  "record_file_delete.sh"|grep "$"|sed-N'1P'|awk '{print $}'`    if[ -z $pid _record_sh] Thennohup./record_file_delete.SH-N $DEFAULT _days-d $RECORD _file_path-s $DEFAULT _mini_space &Else      Echo "record_file_delete.sh is running!"    fi    ###  Else    Echo "Can not find record_file_delete.sh"return0  fi}##################### #videomon_maintain ################### #videomon_maintain () { while true   Do    Sleep 2# # # #Check whether need to delete record filesif[$DEFAULT _file_check-eq1 ]     ThenRecord_file_checkfi     for((i =0; $i < Process_num; i++ ));  Do        Echo$i; PID=`PSAux|grep-Vgrep|grep  "videomon$i-l $VA _log_level"|grep "$"|sed-N'1P'|awk '{print $}'`        if[ -Z $pid] Thenran_videomon_monitor $ifi     Done   Done}################ #start process############## #get_opt [email protected]if[ $? !=0 ] Then   EchoGet_opt Unknow options!Exit1fiVideo_monitor_clean for((i =0; $i < Process_num; i++ )); Doran_videomon_monitor $i DoneVideomon_maintain

Reference http://www.cnblogs.com/kaituorensheng/p/4002697.html

Shell parameter passing