长选项可以被内置的标准getopts作为- " option "的"参数"解析。

这是可移植的本地POSIX shell -不需要外部程序或bashisms。

本指南将长选项作为-选项的参数实现，因此——alpha被getopts视为参数alpha为-，而——bravo=foo被参数bravo=foo视为-。true实参通过shell参数展开获取，更新$OPT和$OPTARG。

在本例中，-b和-c(以及它们的长形式——bravo和——charlie)具有强制实参。长选项的参数出现在等号之后，例如——bravo=foo(长选项的空格分隔符很难实现，参见下文)。

因为它使用了内置的getopts，所以这个解决方案支持像cmd——bravo=foo -ac FILE这样的用法(它组合了选项-a和-c，并将长选项与标准选项交织在一起)，而这里的大多数其他答案要么很难做到，要么无法做到这一点。

die() { echo "$*" >&2; exit 2; }  # complain to STDERR and exit with error
needs_arg() { if [ -z "$OPTARG" ]; then die "No arg for --$OPT option"; fi; }

while getopts ab:c:-: OPT; do
  # support long options: https://stackoverflow.com/a/28466267/519360
  if [ "$OPT" = "-" ]; then   # long option: reformulate OPT and OPTARG
    OPT="${OPTARG%%=*}"       # extract long option name
    OPTARG="${OPTARG#$OPT}"   # extract long option argument (may be empty)
    OPTARG="${OPTARG#=}"      # if long option argument, remove assigning `=`
  fi
  case "$OPT" in
    a | alpha )    alpha=true ;;
    b | bravo )    needs_arg; bravo="$OPTARG" ;;
    c | charlie )  needs_arg; charlie="$OPTARG" ;;
    ??* )          die "Illegal option --$OPT" ;;  # bad long option
    ? )            exit 2 ;;  # bad short option (error reported via getopts)
  esac
done
shift $((OPTIND-1)) # remove parsed options and args from $@ list

When the option is a dash (-), it is a long option. getopts will have parsed the actual long option into $OPTARG, e.g. --bravo=foo originally sets OPT='-' and OPTARG='bravo=foo'. The if stanza sets $OPT to the contents of $OPTARG before the first equals sign (bravo in our example) and then removes that from the beginning of $OPTARG (yielding =foo in this step, or an empty string if there is no =). Finally, we strip the argument's leading =. At this point, $OPT is either a short option (one character) or a long option (2+ characters).

The case then matches either short or long options (the pipe, |, indicates that "or" operation. A long-only option like delta ) delta=true ;; doesn't need a pipe). For short options, getopts automatically complains about options and missing arguments, so we have to replicate those manually using the needs_arg function, which fatally exits when $OPTARG is empty. The ??* condition will match any remaining long option (? matches a single character and * matches zero or more, so ??* matches 2+ characters), allowing us to issue the "Illegal option" error before exiting.

与正常的gnu风格的长选项一样，提供——将停止解析，因此- -- --bravo=4将把$alpha设置为true，但$bravo将保持不变，$1将-bravo=4。我不能说我建议用前导破折号来命名文件，但这是表示它们不是选项的方法。

小错误:如果有人给出了一个无效的单字符长选项(它也不是一个短选项)，这将退出一个错误，但没有消息(这个实现假设它是一个短选项)。您可以在case之前的条件中使用一个额外的变量来跟踪它，然后在最后的case条件中测试它，但我认为这是一个太麻烦的角落情况。

大写变量名:一般情况下，建议保留全大写变量供系统使用。我将$OPT保留为全大写，以与$OPTARG保持一致，但这确实打破了这种约定。我认为这很合适，因为这是系统应该做的事情，它应该是安全的;我还没有听说过任何使用这个变量名的标准。

要抱怨长选项的非预期实参:用翻转测试模拟needs_argg来抱怨一个非预期实参:

no_arg() { if [ -n "$OPTARG" ]; then die "No arg allowed for --$OPT option"; fi; }

要接受带空格分隔参数的长选项:您可以用eval "ARG_B=\"\$$OPTIND\""(或使用bash的间接展开，ARG_B="${!OPTIND}")拉入下一个参数，然后增加$OPTIND，正如这个答案的旧版本所指出的那样，但它不可靠;getopts可以过早地终止，假设参数超出了它的作用域，并且一些实现不太适合手动操作$OPTIND。

我只是偶尔写一些shell脚本，但没有实践经验，所以任何反馈都很感激。

使用@Arvid Requate提出的策略，我们注意到一些用户错误。忘记包含值的用户会意外地将下一个选项的名称视为值:

./getopts_test.sh --loglevel= --toc=TRUE

将导致"loglevel"的值被视为"——toc=TRUE"。这可以 被避免的。

我从http://mwiki.wooledge.org/BashFAQ/035关于手动解析的讨论中改编了一些关于检查CLI用户错误的想法。我在处理"-"和"——"参数时插入了错误检查。

然后我开始摆弄语法，所以这里的任何错误都是我的错，而不是原始作者的错。

我的方法可以帮助那些喜欢输入带等号或不带等号的长字符的用户。也就是说，它对“——loglevel 9”的响应应该与“——loglevel=9”的响应相同。在——/space方法中，不可能确定用户是否忘记了一个参数，因此需要进行一些猜测。

如果用户使用长/等号格式(——opt=)，则=后的空格会触发错误，因为没有提供参数。 如果user有长/空格参数(——opt)，如果后面没有参数(命令结束)或参数以破折号开头，该脚本将导致失败。

In case you are starting out on this, there is an interesting difference between "--opt=value" and "--opt value" formats. With the equal sign, the command line argument is seen as "opt=value" and the work to handle that is string parsing, to separate at the "=". In contrast, with "--opt value", the name of the argument is "opt" and we have the challenge of getting the next value supplied in the command line. That's where @Arvid Requate used ${!OPTIND}, the indirect reference. I still don't understand that, well, at all, and comments in BashFAQ seem to warn against that style (http://mywiki.wooledge.org/BashFAQ/006). BTW, I don't think previous poster's comments about importance of OPTIND=$(( $OPTIND + 1 )) are correct. I mean to say, I see no harm from omitting it.

在该脚本的最新版本中，flag -v表示详细打印输出。

将其保存在一个名为“cli-5.sh”的文件中，使其可执行，其中任何一个都将以预期的方式工作或失败

./cli-5.sh  -v --loglevel=44 --toc  TRUE
./cli-5.sh  -v --loglevel=44 --toc=TRUE
./cli-5.sh --loglevel 7
./cli-5.sh --loglevel=8
./cli-5.sh -l9

./cli-5.sh  --toc FALSE --loglevel=77
./cli-5.sh  --toc=FALSE --loglevel=77

./cli-5.sh   -l99 -t yyy
./cli-5.sh   -l 99 -t yyy

下面是对用户intpu进行错误检查的示例输出

$ ./cli-5.sh  --toc --loglevel=77
ERROR: toc value must not have dash at beginning
$ ./cli-5.sh  --toc= --loglevel=77
ERROR: value for toc undefined

您应该考虑打开-v，因为它会打印OPTIND和OPTARG的内部内容

#/usr/bin/env bash

## Paul Johnson
## 20171016
##

## Combines ideas from
## https://stackoverflow.com/questions/402377/using-getopts-in-bash-shell-script-to-get-long-and-short-command-line-options
## by @Arvid Requate, and http://mwiki.wooledge.org/BashFAQ/035

# What I don't understand yet: 
# In @Arvid REquate's answer, we have 
# val="${!OPTIND}"; OPTIND=$(( $OPTIND + 1 ))
# this works, but I don't understand it!


die() {
    printf '%s\n' "$1" >&2
    exit 1
}

printparse(){
    if [ ${VERBOSE} -gt 0 ]; then
        printf 'Parse: %s%s%s\n' "$1" "$2" "$3" >&2;
    fi
}

showme(){
    if [ ${VERBOSE} -gt 0 ]; then
        printf 'VERBOSE: %s\n' "$1" >&2;
    fi
}


VERBOSE=0
loglevel=0
toc="TRUE"

optspec=":vhl:t:-:"
while getopts "$optspec" OPTCHAR; do

    showme "OPTARG:  ${OPTARG[*]}"
    showme "OPTIND:  ${OPTIND[*]}"
    case "${OPTCHAR}" in
        -)
            case "${OPTARG}" in
                loglevel) #argument has no equal sign
                    opt=${OPTARG}
                    val="${!OPTIND}"
                    ## check value. If negative, assume user forgot value
                    showme "OPTIND is {$OPTIND} {!OPTIND} has value \"${!OPTIND}\""
                    if [[ "$val" == -* ]]; then
                        die "ERROR: $opt value must not have dash at beginning"
                    fi
                    ## OPTIND=$(( $OPTIND + 1 )) # CAUTION! no effect?
                    printparse "--${OPTARG}" "  " "${val}"
                    loglevel="${val}"
                    shift
                    ;;
                loglevel=*) #argument has equal sign
                    opt=${OPTARG%=*}
                    val=${OPTARG#*=}
                    if [ "${OPTARG#*=}" ]; then
                        printparse "--${opt}" "=" "${val}"
                        loglevel="${val}"
                        ## shift CAUTION don't shift this, fails othewise
                    else
                        die "ERROR: $opt value must be supplied"
                    fi
                    ;;
                toc) #argument has no equal sign
                    opt=${OPTARG}
                    val="${!OPTIND}"
                    ## check value. If negative, assume user forgot value
                    showme "OPTIND is {$OPTIND} {!OPTIND} has value \"${!OPTIND}\""
                    if [[ "$val" == -* ]]; then
                        die "ERROR: $opt value must not have dash at beginning"
                    fi
                    ## OPTIND=$(( $OPTIND + 1 )) #??
                    printparse "--${opt}" " " "${val}"
                    toc="${val}"
                    shift
                    ;;
                toc=*) #argument has equal sign
                    opt=${OPTARG%=*}
                    val=${OPTARG#*=}
                    if [ "${OPTARG#*=}" ]; then
                        toc=${val}
                        printparse "--$opt" " -> " "$toc"
                        ##shift ## NO! dont shift this
                    else
                        die "ERROR: value for $opt undefined"
                    fi
                    ;;

                help)
                    echo "usage: $0 [-v] [--loglevel[=]<value>] [--toc[=]<TRUE,FALSE>]" >&2
                    exit 2
                    ;;
                *)
                    if [ "$OPTERR" = 1 ] && [ "${optspec:0:1}" != ":" ]; then
                        echo "Unknown option --${OPTARG}" >&2
                    fi
                    ;;
            esac;;
        h|-\?|--help)
            ## must rewrite this for all of the arguments
            echo "usage: $0 [-v] [--loglevel[=]<value>] [--toc[=]<TRUE,FALSE>]" >&2
            exit 2
            ;;
        l)
            loglevel=${OPTARG}
            printparse "-l" " "  "${loglevel}"
            ;;
        t)
            toc=${OPTARG}
            ;;
        v)
            VERBOSE=1
            ;;

        *)
            if [ "$OPTERR" != 1 ] || [ "${optspec:0:1}" = ":" ]; then
                echo "Non-option argument: '-${OPTARG}'" >&2
            fi
            ;;
    esac
done



echo "
After Parsing values
"
echo "loglevel  $loglevel" 
echo "toc  $toc"

#!/bin/bash
while getopts "abc:d:" flag
do
  case $flag in
    a) echo "[getopts:$OPTIND]==> -$flag";;
    b) echo "[getopts:$OPTIND]==> -$flag";;
    c) echo "[getopts:$OPTIND]==> -$flag $OPTARG";;
    d) echo "[getopts:$OPTIND]==> -$flag $OPTARG";;
  esac
done

shift $((OPTIND-1))
echo "[otheropts]==> $@"

exit

.

#!/bin/bash
until [ -z "$1" ]; do
  case $1 in
    "--dlong")
      shift
      if [ "${1:1:0}" != "-" ]
      then
        echo "==> dlong $1"
        shift
      fi;;
    *) echo "==> other $1"; shift;;
  esac
done
exit

看一下shFlags，它是一个可移植的shell库(意思是:sh, bash, dash, ksh, zsh在Linux, Solaris等上)。

它使得添加新标志就像在脚本中添加一行一样简单，并且它提供了一个自动生成的用法函数。

这是一个简单的Hello, world!使用shFlag:

#!/bin/sh

# source shflags from current directory
. ./shflags

# define a 'name' command-line string flag
DEFINE_string 'name' 'world' 'name to say hello to' 'n'

# parse the command-line
FLAGS "$@" || exit 1
eval set -- "${FLAGS_ARGV}"

# say hello
echo "Hello, ${FLAGS_name}!"

对于具有支持长选项的增强getopt的操作系统(例如Linux)，您可以这样做:

$ ./hello_world.sh --name Kate
Hello, Kate!

对于其他情况，您必须使用短选项:

$ ./hello_world.sh -n Kate
Hello, Kate!

添加一个新标志就像添加一个新的DEFINE_调用一样简单。

发明了另一个版本的轮子……

这个函数(希望)是一个posix兼容的普通bourne shell替换GNU getopt。它支持短/长选项，可以接受强制/可选/无参数，并且指定选项的方式几乎与GNU getopt相同，因此转换是微不足道的。

当然，要放入脚本中，这仍然是相当大的代码块，但它大约是众所周知的getopt_long shell函数的一半行数，并且在您只想替换现有的GNU getopt使用的情况下可能更可取。

这是相当新的代码，所以是YMMV(如果因为某种原因它实际上与POSIX不兼容，请务必告诉我——可移植性是一开始的意图，但我没有一个有用的POSIX测试环境)。

代码和示例用法如下:

#!/bin/sh
# posix_getopt shell function
# Author: Phil S.
# Version: 1.0
# Created: 2016-07-05
# URL: http://stackoverflow.com/a/37087374/324105

# POSIX-compatible argument quoting and parameter save/restore
# http://www.etalabs.net/sh_tricks.html
# Usage:
# parameters=$(save "$@") # save the original parameters.
# eval "set -- ${parameters}" # restore the saved parameters.
save () {
    local param
    for param; do
        printf %s\\n "$param" \
            | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/"
    done
    printf %s\\n " "
}

# Exit with status $1 after displaying error message $2.
exiterr () {
    printf %s\\n "$2" >&2
    exit $1
}

# POSIX-compatible command line option parsing.
# This function supports long options and optional arguments, and is
# a (largely-compatible) drop-in replacement for GNU getopt.
#
# Instead of:
# opts=$(getopt -o "$shortopts" -l "$longopts" -- "$@")
# eval set -- ${opts}
#
# We instead use:
# opts=$(posix_getopt "$shortopts" "$longopts" "$@")
# eval "set -- ${opts}"
posix_getopt () { # args: "$shortopts" "$longopts" "$@"
    local shortopts longopts \
          arg argtype getopt nonopt opt optchar optword suffix

    shortopts="$1"
    longopts="$2"
    shift 2

    getopt=
    nonopt=
    while [ $# -gt 0 ]; do
        opt=
        arg=
        argtype=
        case "$1" in
            # '--' means don't parse the remaining options
            ( -- ) {
                getopt="${getopt}$(save "$@")"
                shift $#
                break
            };;
            # process short option
            ( -[!-]* ) {         # -x[foo]
                suffix=${1#-?}   # foo
                opt=${1%$suffix} # -x
                optchar=${opt#-} # x
                case "${shortopts}" in
                    ( *${optchar}::* ) { # optional argument
                        argtype=optional
                        arg="${suffix}"
                        shift
                    };;
                    ( *${optchar}:* ) { # required argument
                        argtype=required
                        if [ -n "${suffix}" ]; then
                            arg="${suffix}"
                            shift
                        else
                            case "$2" in
                                ( -* ) exiterr 1 "$1 requires an argument";;
                                ( ?* ) arg="$2"; shift 2;;
                                (  * ) exiterr 1 "$1 requires an argument";;
                            esac
                        fi
                    };;
                    ( *${optchar}* ) { # no argument
                        argtype=none
                        arg=
                        shift
                        # Handle multiple no-argument parameters combined as
                        # -xyz instead of -x -y -z. If we have just shifted
                        # parameter -xyz, we now replace it with -yz (which
                        # will be processed in the next iteration).
                        if [ -n "${suffix}" ]; then
                            eval "set -- $(save "-${suffix}")$(save "$@")"
                        fi
                    };;
                    ( * ) exiterr 1 "Unknown option $1";;
                esac
            };;
            # process long option
            ( --?* ) {            # --xarg[=foo]
                suffix=${1#*=}    # foo (unless there was no =)
                if [ "${suffix}" = "$1" ]; then
                    suffix=
                fi
                opt=${1%=$suffix} # --xarg
                optword=${opt#--} # xarg
                case ",${longopts}," in
                    ( *,${optword}::,* ) { # optional argument
                        argtype=optional
                        arg="${suffix}"
                        shift
                    };;
                    ( *,${optword}:,* ) { # required argument
                        argtype=required
                        if [ -n "${suffix}" ]; then
                            arg="${suffix}"
                            shift
                        else
                            case "$2" in
                                ( -* ) exiterr 1 \
                                       "--${optword} requires an argument";;
                                ( ?* ) arg="$2"; shift 2;;
                                (  * ) exiterr 1 \
                                       "--${optword} requires an argument";;
                            esac
                        fi
                    };;
                    ( *,${optword},* ) { # no argument
                        if [ -n "${suffix}" ]; then
                            exiterr 1 "--${optword} does not take an argument"
                        fi
                        argtype=none
                        arg=
                        shift
                    };;
                    ( * ) exiterr 1 "Unknown option $1";;
                esac
            };;
            # any other parameters starting with -
            ( -* ) exiterr 1 "Unknown option $1";;
            # remember non-option parameters
            ( * ) nonopt="${nonopt}$(save "$1")"; shift;;
        esac

        if [ -n "${opt}" ]; then
            getopt="${getopt}$(save "$opt")"
            case "${argtype}" in
                ( optional|required ) {
                    getopt="${getopt}$(save "$arg")"
                };;
            esac
        fi
    done

    # Generate function output, suitable for:
    # eval "set -- $(posix_getopt ...)"
    printf %s "${getopt}"
    if [ -n "${nonopt}" ]; then
        printf %s "$(save "--")${nonopt}"
    fi
}

使用示例:

# Process command line options
shortopts="hvd:c::s::L:D"
longopts="help,version,directory:,client::,server::,load:,delete"
#opts=$(getopt -o "$shortopts" -l "$longopts" -n "$(basename $0)" -- "$@")
opts=$(posix_getopt "$shortopts" "$longopts" "$@")
if [ $? -eq 0 ]; then
    #eval set -- ${opts}
    eval "set -- ${opts}"
    while [ $# -gt 0 ]; do
        case "$1" in
            ( --                ) shift; break;;
            ( -h|--help         ) help=1; shift; break;;
            ( -v|--version      ) version_help=1; shift; break;;
            ( -d|--directory    ) dir=$2; shift 2;;
            ( -c|--client       ) useclient=1; client=$2; shift 2;;
            ( -s|--server       ) startserver=1; server_name=$2; shift 2;;
            ( -L|--load         ) load=$2; shift 2;;
            ( -D|--delete       ) delete=1; shift;;
        esac
    done
else
    shorthelp=1 # getopt returned (and reported) an error.
fi

内置的getopts只解析短选项(ksh93除外)， 但是您仍然可以添加几行脚本来使getopts处理长选项。

以下是在http://www.uxora.com/unix/shell-script/22-handle-long-options-with-getopts中找到的部分代码

  #== set short options ==#
SCRIPT_OPTS=':fbF:B:-:h'
  #== set long options associated with short one ==#
typeset -A ARRAY_OPTS
ARRAY_OPTS=(
    [foo]=f
    [bar]=b
    [foobar]=F
    [barfoo]=B
    [help]=h
    [man]=h
)

  #== parse options ==#
while getopts ${SCRIPT_OPTS} OPTION ; do
    #== translate long options to short ==#
    if [[ "x$OPTION" == "x-" ]]; then
        LONG_OPTION=$OPTARG
        LONG_OPTARG=$(echo $LONG_OPTION | grep "=" | cut -d'=' -f2)
        LONG_OPTIND=-1
        [[ "x$LONG_OPTARG" = "x" ]] && LONG_OPTIND=$OPTIND || LONG_OPTION=$(echo $OPTARG | cut -d'=' -f1)
        [[ $LONG_OPTIND -ne -1 ]] && eval LONG_OPTARG="\$$LONG_OPTIND"
        OPTION=${ARRAY_OPTS[$LONG_OPTION]}
        [[ "x$OPTION" = "x" ]] &&  OPTION="?" OPTARG="-$LONG_OPTION"

        if [[ $( echo "${SCRIPT_OPTS}" | grep -c "${OPTION}:" ) -eq 1 ]]; then
            if [[ "x${LONG_OPTARG}" = "x" ]] || [[ "${LONG_OPTARG}" = -* ]]; then 
                OPTION=":" OPTARG="-$LONG_OPTION"
            else
                OPTARG="$LONG_OPTARG";
                if [[ $LONG_OPTIND -ne -1 ]]; then
                    [[ $OPTIND -le $Optnum ]] && OPTIND=$(( $OPTIND+1 ))
                    shift $OPTIND
                    OPTIND=1
                fi
            fi
        fi
    fi

    #== options follow by another option instead of argument ==#
    if [[ "x${OPTION}" != "x:" ]] && [[ "x${OPTION}" != "x?" ]] && [[ "${OPTARG}" = -* ]]; then 
        OPTARG="$OPTION" OPTION=":"
    fi

    #== manage options ==#
    case "$OPTION" in
        f  ) foo=1 bar=0                    ;;
        b  ) foo=0 bar=1                    ;;
        B  ) barfoo=${OPTARG}               ;;
        F  ) foobar=1 && foobar_name=${OPTARG} ;;
        h ) usagefull && exit 0 ;;
        : ) echo "${SCRIPT_NAME}: -$OPTARG: option requires an argument" >&2 && usage >&2 && exit 99 ;;
        ? ) echo "${SCRIPT_NAME}: -$OPTARG: unknown option" >&2 && usage >&2 && exit 99 ;;
    esac
done
shift $((${OPTIND} - 1))

下面是一个测试:

# Short options test
$ ./foobar_any_getopts.sh -bF "Hello world" -B 6 file1 file2
foo=0 bar=1
barfoo=6
foobar=1 foobar_name=Hello world
files=file1 file2

# Long and short options test
$ ./foobar_any_getopts.sh --bar -F Hello --barfoo 6 file1 file2
foo=0 bar=1
barfoo=6
foobar=1 foobar_name=Hello
files=file1 file2

另外，在最近的Korn Shell ksh93中，getopts可以自然地解析长选项，甚至显示类似的手册页。(参见http://www.uxora.com/unix/shell-script/20-getopts-with-man-page-and-long-options)