Comparison of three methods for passing parameters in Shell scripts

Comparison of three methods for passing parameters in Shell scripts

This article mainly introduces the comparison of three methods for passing parameters in Shell scripts. This article provides a sample code that contains detailed annotations in the Code. For more information, see

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#! /Bin/bash # Extracting command text_text_line options as parameters   Help_info (){ Echo "NAME" Echo "\ t $0" Echo "SYNOPSIS" Echo "\ t $0 is a shell test about process options" Echo "DESCRIPTION" Echo "\ toption like-a-B param1-c param2-d" }   If [$ #-lt 0] Then Help_info Fi   Nomal_opts_act () { Echo-e "\ n ### nomal_opts_act ###\ n"   While [-n "$1"] Do Case "$1" in -) Echo "Found the-a option" ;; -B) Echo "Found the-B option" Echo "The parameter follow-B is $2" Shift ;; -C) Echo "Found the-c option" Echo "The parameter follow-c is $2" Shift ;; -D) Echo "Found the-d option" ;; *) Echo "$1 is not an option" ;; Esac Shift Done }   # Using shell commands to build options for parsing can be implemented according to your own ideas # Advantages: self-built, not impossible, unexpected # Disadvantages: Trouble   Getopt_act () { Echo-e "\ n ### getopt_act ###\ n"   GETOPTOUT = 'getopt AB: c: d "$ @"' Set -- $ GETOPTOUT While [-n "$1"] Do Case $1 in -) Echo "Found the-a option" ;; -B) Echo "Found the-B option" Echo "The parameter follow-B is" $2 "" Shift ;; -C) Echo "Found the-c option" Echo "The parameter follow-c is" $2 "" Shift ;; -D) Echo "Found the-d option" ;; --) Shift Break ;; *) Echo "Unknow option:" $1 "" ;; Esac Shift Done   Param_index = 1 For param in "$ @" Do Echo "Parameter $ param_index: $ param" Param_index = $ [$ param_index + 1] Done }   # Use the getopt command to parse options and Parameters # Advantage: Compared with getopts, It is semi-automated parsing. Options and parameters are automatically organized and separated by the -- symbol. # Disadvantages: disadvantages of getopts #1. You need to work with the set -- command. It is not required. You need to manually shift #2. Space is not supported in option parameters, such as-a-B dog-c "earth moon"-d-f param1 param2, parsing errors will occur.   Getopts_act () { Echo-e "\ n ### getopts_act ###\ n" While getopts: AB: c: d ARGS Do Case $ ARGS in A) Echo "Found the-a option" ;; B) Echo "Found the-B option" Echo "The parameter follow-B is $ OPTARG" ;; C) Echo "Found the-c option" Echo "The parameter follow-c is $ OPTARG" ;; D) Echo "Found the-d option" ;; *) Echo "Unknow option: $ ARGS" ;; Esac Done   Shift $ [$ OPTIND-1] Param_index = 1 For param in "$ @" Do Echo "Parameter $ param_index: $ param" Param_index = $ [$ param_index + 1] Done }   # Getopts Command Parsing options and Parameters # Advantage: the parameter can contain spaces such as-c "earth moon" # There can be no space between option letters and parameter values, for example,-bdog # Undefined options can be bound? Output # Unknow option :?   Nomal_opts_act-a-B dog-c earth-d-f param1 param2 Getopts_act-a-B dog-c "earth moon"-d-f param1 param2 Getopt_act-a-B dog-c earth-d-f param1 param2

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