一些参考

Question

我知道我可以轻松地在bash中找到这样的定位参数：

$0或$1

我希望能够使用这样的标志选项来指定每个参数的用途：

mysql -u user -h host

通过标记而不是按位置获取-u param值和-h param值的最佳方法是什么？

Answer 1

此示例使用Bash的内置getopts命令，来自Google Shell Style Guide：

a_flag=''
b_flag=''
files=''
verbose='false'

print_usage() {
  printf "Usage: ..."
}

while getopts 'abf:v' flag; do
  case "${flag}" in
    a) a_flag='true' ;;
    b) b_flag='true' ;;
    f) files="${OPTARG}" ;;
    v) verbose='true' ;;
    *) print_usage
       exit 1 ;;
  esac
done

注意：如果一个字符后跟一个冒号（例如f:），那么该选项应该有一个参数。

使用示例：./script -v -a -b -f filename

使用getopts比接受的答案有几个优点：

while条件更具可读性，并显示了可接受的选项
清洁代码;不计算参数数量和转移
您可以加入选项（例如-a -b -c→-abc）

然而，一个很大的缺点是它不支持长选项，只支持单字符选项。

Answer 2

这是我经常使用的习语：

while test $# -gt 0; do
        case "$1" in
                -h|--help)
                        echo "$package - attempt to capture frames"
                        echo " "
                        echo "$package [options] application [arguments]"
                        echo " "
                        echo "options:"
                        echo "-h, --help                show brief help"
                        echo "-a, --action=ACTION       specify an action to use"
                        echo "-o, --output-dir=DIR      specify a directory to store output in"
                        exit 0
                        ;;
                -a)
                        shift
                        if test $# -gt 0; then
                                export PROCESS=$1
                        else
                                echo "no process specified"
                                exit 1
                        fi
                        shift
                        ;;
                --action*)
                        export PROCESS=`echo $1 | sed -e 's/^[^=]*=//g'`
                        shift
                        ;;
                -o)
                        shift
                        if test $# -gt 0; then
                                export OUTPUT=$1
                        else
                                echo "no output dir specified"
                                exit 1
                        fi
                        shift
                        ;;
                --output-dir*)
                        export OUTPUT=`echo $1 | sed -e 's/^[^=]*=//g'`
                        shift
                        ;;
                *)
                        break
                        ;;
        esac
done

要点是：

$#是参数的数量
while循环查看提供的所有参数，在case语句
shift取走第一个。您可以在case语句中多次移动以获取多个值。

Answer 3

getopt是你的朋友..一个简单的例子：

function f () {
TEMP=`getopt --long -o "u:h:" "$@"`
eval set -- "$TEMP"
while true ; do
    case "$1" in
        -u )
            user=$2
            shift 2
        ;;
        -h )
            host=$2
            shift 2
        ;;
        *)
            break
        ;;
    esac 
done;

echo "user = $user, host = $host"
}

f -u myself -h some_host

/ usr / bin目录中应该有各种示例。

Answer 4

我认为这可以作为您想要实现的更简单的例子。无需使用外部工具。内置工具的Bash可以为您完成工作。

function DOSOMETHING {

   while test $# -gt 0; do
           case "$1" in
                -first)
                    shift
                    first_argument=$1
                    shift
                    ;;
                -last)
                    shift
                    last_argument=$1
                    shift
                    ;;
                *)
                   echo "$1 is not a recognized flag!"
                   return 1;
                   ;;
          esac
  done  

  echo "First argument : $first_argument";
  echo "Last argument : $last_argument";
 }

这将允许您使用标志，因此无论您传递参数的顺序，您都将获得正确的行为。

示例：

 DOSOMETHING -last "Adios" -first "Hola"

输出：

 First argument : Hola
 Last argument : Adios

您可以将此功能添加到个人资料中，也可以将其放在脚本中。

谢谢！

编辑：将其另存为文件，然后将其作为yourfile.sh -last "Adios" -first "Hola"

执行

#!/bin/bash
while test $# -gt 0; do
           case "$1" in
                -first)
                    shift
                    first_argument=$1
                    shift
                    ;;
                -last)
                    shift
                    last_argument=$1
                    shift
                    ;;
                *)
                   echo "$1 is not a recognized flag!"
                   return 1;
                   ;;
          esac
  done  

  echo "First argument : $first_argument";
  echo "Last argument : $last_argument";

Answer 5

另一个替代方案是使用类似下面的示例，它允许您使用长 - 图像或短 -i 标记，并允许编译 -i =“example.jpg”或单独的 -i example.jpg 传递参数的方法。

# declaring a couple of associative arrays
declare -A arguments=();  
declare -A variables=();

# declaring an index integer
declare -i index=1;

# any variables you want to use here
# on the left left side is argument label or key (entered at the command line along with it's value) 
# on the right side is the variable name the value of these arguments should be mapped to.
# (the examples above show how these are being passed into this script)
variables["-gu"]="git_user";  
variables["--git-user"]="git_user";  
variables["-gb"]="git_branch";  
variables["--git-branch"]="git_branch";  
variables["-dbr"]="db_fqdn";  
variables["--db-redirect"]="db_fqdn";  
variables["-e"]="environment";  
variables["--environment"]="environment";

# $@ here represents all arguments passed in
for i in "$@"  
do  
  arguments[$index]=$i;
  prev_index="$(expr $index - 1)";

  # this if block does something akin to "where $i contains ="
  # "%=*" here strips out everything from the = to the end of the argument leaving only the label
  if [[ $i == *"="* ]]
    then argument_label=${i%=*} 
    else argument_label=${arguments[$prev_index]}
  fi

  # this if block only evaluates to true if the argument label exists in the variables array
  if [[ -n ${variables[$argument_label]} ]]
    then
        # dynamically creating variables names using declare
        # "#$argument_label=" here strips out the label leaving only the value
        if [[ $i == *"="* ]]
            then declare ${variables[$argument_label]}=${i#$argument_label=} 
            else declare ${variables[$argument_label]}=${arguments[$index]}
        fi
  fi

  index=index+1;
done;

# then you could simply use the variables like so:
echo "$git_user";

Answer 6

我喜欢罗伯特麦克马汉在这里的最佳答案，因为它似乎是最易于使用的任何脚本的可共享包含文件。但似乎有一个缺陷，即行if [[ -n ${variables[$argument_label]} ]]抛出了消息，＆＃34;变量：坏数组下标＆＃34;。我没有代表发表评论，我怀疑这是正确的修复，＆＃39;但将if包裹在if [[ -n $argument_label ]] ; then中会将其清理干净。

这是我最终得到的代码，如果您知道更好的方法，请在罗伯特的答案中添加评论。

包含文件＆＃34; flags-declares.sh＆＃34;

# declaring a couple of associative arrays
declare -A arguments=();
declare -A variables=();

# declaring an index integer
declare -i index=1;

包含文件＆＃34; flags-arguments.sh＆＃34;

# $@ here represents all arguments passed in
for i in "$@"
do
  arguments[$index]=$i;
  prev_index="$(expr $index - 1)";

  # this if block does something akin to "where $i contains ="
  # "%=*" here strips out everything from the = to the end of the argument leaving only the label
  if [[ $i == *"="* ]]
    then argument_label=${i%=*}
    else argument_label=${arguments[$prev_index]}
  fi

  if [[ -n $argument_label ]] ; then
    # this if block only evaluates to true if the argument label exists in the variables array
    if [[ -n ${variables[$argument_label]} ]] ; then
      # dynamically creating variables names using declare
      # "#$argument_label=" here strips out the label leaving only the value
      if [[ $i == *"="* ]]
        then declare ${variables[$argument_label]}=${i#$argument_label=} 
        else declare ${variables[$argument_label]}=${arguments[$index]}
      fi
    fi
  fi

  index=index+1;
done;

你的＆＃34; script.sh＆＃34;

. bin/includes/flags-declares.sh

# any variables you want to use here
# on the left left side is argument label or key (entered at the command line along with it's value) 
# on the right side is the variable name the value of these arguments should be mapped to.
# (the examples above show how these are being passed into this script)
variables["-gu"]="git_user";
variables["--git-user"]="git_user";
variables["-gb"]="git_branch";
variables["--git-branch"]="git_branch";
variables["-dbr"]="db_fqdn";
variables["--db-redirect"]="db_fqdn";
variables["-e"]="environment";
variables["--environment"]="environment";

. bin/includes/flags-arguments.sh

# then you could simply use the variables like so:
echo "$git_user";
echo "$git_branch";
echo "$db_fqdn";
echo "$environment";

Answer 7

我提出了一个简单的TLDR：未启动的示例。

创建一个名为helloworld.sh的bash脚本

#!/bin/bash

while getopts "n:" arg; do
  case $arg in
    n) Name=$OPTARG;;
  esac
done

echo "Hello $Name!"

然后，您可以在执行脚本时传递可选参数-n。

以这种方式执行脚本：

$ bash helloworld.sh -n 'World'

输出

$ Hello World!

注释

如果您想使用多个参数：

使用更多参数将while getops "n:" arg: do扩展为 while getops "n:o:p:" arg: do
通过额外的变量分配扩展大小写开关。例如o) Option=$OPTARG和p) Parameter=$OPTARG

Answer 8

如果您熟悉Python argparse，并且不介意调用python来解析bash参数，那么我发现有一段代码非常有用并且非常易于使用，称为argparse-bash https://github.com/nhoffman/argparse-bash

示例来自他们的example.sh脚本：

#!/bin/bash

source $(dirname $0)/argparse.bash || exit 1
argparse "$@" <<EOF || exit 1
parser.add_argument('infile')
parser.add_argument('outfile')
parser.add_argument('-a', '--the-answer', default=42, type=int,
                    help='Pick a number [default %(default)s]')
parser.add_argument('-d', '--do-the-thing', action='store_true',
                    default=False, help='store a boolean [default %(default)s]')
parser.add_argument('-m', '--multiple', nargs='+',
                    help='multiple values allowed')
EOF

echo required infile: "$INFILE"
echo required outfile: "$OUTFILE"
echo the answer: "$THE_ANSWER"
echo -n do the thing?
if [[ $DO_THE_THING ]]; then
    echo " yes, do it"
else
    echo " no, do not do it"
fi
echo -n "arg with multiple values: "
for a in "${MULTIPLE[@]}"; do
    echo -n "[$a] "
done
echo

Answer 9

#!/bin/bash

if getopts "n:" arg; then
  echo "Welcome $OPTARG"
fi

将其另存为sample.sh 并尝试运行

sh sample.sh -n John

在您的终端上。

Answer 10

我在将getopts与多个标志一起使用时遇到了麻烦，因此我编写了这段代码。它使用模态变量来检测标志，并使用这些标志为变量分配参数。

请注意，如果标志中不应该包含参数，则可以执行除设置CURRENTFLAG之外的其他操作。

    for MYFIELD in "$@"; do

        CHECKFIRST=`echo $MYFIELD | cut -c1`

        if [ "$CHECKFIRST" == "-" ]; then
            mode="flag"
        else
            mode="arg"
        fi

        if [ "$mode" == "flag" ]; then
            case $MYFIELD in
                -a)
                    CURRENTFLAG="VARIABLE_A"
                    ;;
                -b)
                    CURRENTFLAG="VARIABLE_B"
                    ;;
                -c)
                    CURRENTFLAG="VARIABLE_C"
                    ;;
            esac
        elif [ "$mode" == "arg" ]; then
            case $CURRENTFLAG in
                VARIABLE_A)
                    VARIABLE_A="$MYFIELD"
                    ;;
                VARIABLE_B)
                    VARIABLE_B="$MYFIELD"
                    ;;
                VARIABLE_C)
                    VARIABLE_C="$MYFIELD"
                    ;;
            esac
        fi
    done

Answer 11

这是我的解决方案。我希望能够处理不带连字符，带有一个连字符和带有两个连字符的布尔标志，以及带有一个和两个连字符的参数/值分配。

# Handle multiple types of arguments and prints some variables
#
# Boolean flags
# 1) No hyphen
#    create   Assigns `true` to the variable `CREATE`.
#             Default is `CREATE_DEFAULT`.
#    delete   Assigns true to the variable `DELETE`.
#             Default is `DELETE_DEFAULT`.
# 2) One hyphen
#      a      Assigns `true` to a. Default is `false`.
#      b      Assigns `true` to b. Default is `false`.
# 3) Two hyphens
#    cats     Assigns `true` to `cats`. By default is not set.
#    dogs     Assigns `true` to `cats`. By default is not set.
#
# Parameter - Value
# 1) One hyphen
#      c      Assign any value you want
#      d      Assign any value you want
#
# 2) Two hyphens
#   ... Anything really, whatever two-hyphen argument is given that is not
#       defined as flag, will be defined with the next argument after it.
#
# Example:
# ./parser_example.sh delete -a -c VA_1 --cats --dir /path/to/dir
parser() {
    # Define arguments with one hyphen that are boolean flags
    HYPHEN_FLAGS="a b"
    # Define arguments with two hyphens that are boolean flags
    DHYPHEN_FLAGS="cats dogs"

    # Iterate over all the arguments
    while [ $# -gt 0 ]; do
        # Handle the arguments with no hyphen
        if [[ $1 != "-"* ]]; then
            echo "Argument with no hyphen!"
            echo $1
            # Assign true to argument $1
            declare $1=true
            # Shift arguments by one to the left
            shift
        # Handle the arguments with one hyphen
        elif [[ $1 == "-"[A-Za-z0-9]* ]]; then
            # Handle the flags
            if [[ $HYPHEN_FLAGS == *"${1/-/}"* ]]; then
                echo "Argument with one hyphen flag!"
                echo $1
                # Remove the hyphen from $1
                local param="${1/-/}"
                # Assign true to $param
                declare $param=true
                # Shift by one
                shift
            # Handle the parameter-value cases
            else
                echo "Argument with one hyphen value!"
                echo $1 $2
                # Remove the hyphen from $1
                local param="${1/-/}"
                # Assign argument $2 to $param
                declare $param="$2"
                # Shift by two
                shift 2
            fi
        # Handle the arguments with two hyphens
        elif [[ $1 == "--"[A-Za-z0-9]* ]]; then
            # NOTE: For double hyphen I am using `declare -g $param`.
            #   This is the case because I am assuming that's going to be
            #   the final name of the variable
            echo "Argument with two hypens!"
            # Handle the flags
            if [[ $DHYPHEN_FLAGS == *"${1/--/}"* ]]; then
                echo $1 true
                # Remove the hyphens from $1
                local param="${1/--/}"
                # Assign argument $2 to $param
                declare -g $param=true
                # Shift by two
                shift
            # Handle the parameter-value cases
            else
                echo $1 $2
                # Remove the hyphens from $1
                local param="${1/--/}"
                # Assign argument $2 to $param
                declare -g $param="$2"
                # Shift by two
                shift 2
            fi
        fi

    done
    # Default value for arguments with no hypheb
    CREATE=${create:-'CREATE_DEFAULT'}
    DELETE=${delete:-'DELETE_DEFAULT'}
    # Default value for arguments with one hypen flag
    VAR1=${a:-false}
    VAR2=${b:-false}
    # Default value for arguments with value
    # NOTE1: This is just for illustration in one line. We can well create
    #   another function to handle this. Here I am handling the cases where
    #   we have a full named argument and a contraction of it.
    #   For example `--arg1` can be also set with `-c`.
    # NOTE2: What we are doing here is to check if $arg is defined. If not,
    #   check if $c was defined. If not, assign the default value "VD_"
    VAR3=$(if [[ $arg1 ]]; then echo $arg1; else echo ${c:-"VD_1"}; fi)
    VAR4=$(if [[ $arg2 ]]; then echo $arg2; else echo ${d:-"VD_2"}; fi)
}


# Pass all the arguments given to the script to the parser function
parser "$@"


echo $CREATE $DELETE $VAR1 $VAR2 $VAR3 $VAR4 $cats $dir

一些参考

找到了主要过程here。
有关将所有参数传递给函数here的更多信息。
有关默认值here的更多信息。
有关declare的更多信息，请执行$ bash -c "help declare"。
有关shift的更多信息，请执行$ bash -c "help shift"。

如何在Bash中使用标志获取参数

11 个答案:

一些参考