比如,我有一个脚本,用这行代码调用:
./myscript -vfd ./foo/bar/someFile -o /fizz/someOtherFile
或者这个:
./myscript -v -f -d -o /fizz/someOtherFile ./foo/bar/someFile
什么是公认的解析方式,以便在每种情况下(或两者的某种组合)$v、$f和$d都将设置为true,而$outFile将等于/fiz/someOtherFile?
比如,我有一个脚本,用这行代码调用:
./myscript -vfd ./foo/bar/someFile -o /fizz/someOtherFile
或者这个:
./myscript -v -f -d -o /fizz/someOtherFile ./foo/bar/someFile
什么是公认的解析方式,以便在每种情况下(或两者的某种组合)$v、$f和$d都将设置为true,而$outFile将等于/fiz/someOtherFile?
当前回答
我给你一个函数parse_params,它将从命令行解析参数。
这是一个纯Bash解决方案,没有额外的实用程序。不会污染全球范围。轻松地返回简单易用的变量,您可以在这些变量上构建进一步的逻辑。params前面的破折号数量无关紧要(--all等于-all等于all=all)
下面的脚本是复制粘贴工作演示。请参见show_use函数以了解如何使用parse_param。
限制:
不支持空格分隔的参数(-d 1)参数名称将丢失破折号,因此--any参数和-anyparam等效eval$(parse_params“$@”)必须在bash函数中使用(它在全局范围内不起作用)
#!/bin/bash
# Universal Bash parameter parsing
# Parse equal sign separated params into named local variables
# Standalone named parameter value will equal its param name (--force creates variable $force=="force")
# Parses multi-valued named params into an array (--path=path1 --path=path2 creates ${path[*]} array)
# Puts un-named params as-is into ${ARGV[*]} array
# Additionally puts all named params as-is into ${ARGN[*]} array
# Additionally puts all standalone "option" params as-is into ${ARGO[*]} array
# @author Oleksii Chekulaiev
# @version v1.4.1 (Jul-27-2018)
parse_params ()
{
local existing_named
local ARGV=() # un-named params
local ARGN=() # named params
local ARGO=() # options (--params)
echo "local ARGV=(); local ARGN=(); local ARGO=();"
while [[ "$1" != "" ]]; do
# Escape asterisk to prevent bash asterisk expansion, and quotes to prevent string breakage
_escaped=${1/\*/\'\"*\"\'}
_escaped=${_escaped//\'/\\\'}
_escaped=${_escaped//\"/\\\"}
# If equals delimited named parameter
nonspace="[^[:space:]]"
if [[ "$1" =~ ^${nonspace}${nonspace}*=..* ]]; then
# Add to named parameters array
echo "ARGN+=('$_escaped');"
# key is part before first =
local _key=$(echo "$1" | cut -d = -f 1)
# Just add as non-named when key is empty or contains space
if [[ "$_key" == "" || "$_key" =~ " " ]]; then
echo "ARGV+=('$_escaped');"
shift
continue
fi
# val is everything after key and = (protect from param==value error)
local _val="${1/$_key=}"
# remove dashes from key name
_key=${_key//\-}
# skip when key is empty
# search for existing parameter name
if (echo "$existing_named" | grep "\b$_key\b" >/dev/null); then
# if name already exists then it's a multi-value named parameter
# re-declare it as an array if needed
if ! (declare -p _key 2> /dev/null | grep -q 'declare \-a'); then
echo "$_key=(\"\$$_key\");"
fi
# append new value
echo "$_key+=('$_val');"
else
# single-value named parameter
echo "local $_key='$_val';"
existing_named=" $_key"
fi
# If standalone named parameter
elif [[ "$1" =~ ^\-${nonspace}+ ]]; then
# remove dashes
local _key=${1//\-}
# Just add as non-named when key is empty or contains space
if [[ "$_key" == "" || "$_key" =~ " " ]]; then
echo "ARGV+=('$_escaped');"
shift
continue
fi
# Add to options array
echo "ARGO+=('$_escaped');"
echo "local $_key=\"$_key\";"
# non-named parameter
else
# Escape asterisk to prevent bash asterisk expansion
_escaped=${1/\*/\'\"*\"\'}
echo "ARGV+=('$_escaped');"
fi
shift
done
}
#--------------------------- DEMO OF THE USAGE -------------------------------
show_use ()
{
eval $(parse_params "$@")
# --
echo "${ARGV[0]}" # print first unnamed param
echo "${ARGV[1]}" # print second unnamed param
echo "${ARGN[0]}" # print first named param
echo "${ARG0[0]}" # print first option param (--force)
echo "$anyparam" # print --anyparam value
echo "$k" # print k=5 value
echo "${multivalue[0]}" # print first value of multi-value
echo "${multivalue[1]}" # print second value of multi-value
[[ "$force" == "force" ]] && echo "\$force is set so let the force be with you"
}
show_use "param 1" --anyparam="my value" param2 k=5 --force --multi-value=test1 --multi-value=test2
其他回答
如果您正在制作可与其他实用程序互换的脚本,下面的灵活性可能很有用。
以下任一项:
command -x=myfilename.ext --another_switch
Or:
command -x myfilename.ext --another_switch
代码如下:
STD_IN=0
prefix=""
key=""
value=""
for keyValue in "$@"
do
case "${prefix}${keyValue}" in
-i=*|--input_filename=*) key="-i"; value="${keyValue#*=}";;
-ss=*|--seek_from=*) key="-ss"; value="${keyValue#*=}";;
-t=*|--play_seconds=*) key="-t"; value="${keyValue#*=}";;
-|--stdin) key="-"; value=1;;
*) value=$keyValue;;
esac
case $key in
-i) MOVIE=$(resolveMovie "${value}"); prefix=""; key="";;
-ss) SEEK_FROM="${value}"; prefix=""; key="";;
-t) PLAY_SECONDS="${value}"; prefix=""; key="";;
-) STD_IN=${value}; prefix=""; key="";;
*) prefix="${keyValue}=";;
esac
done
另一个Shell参数分析器(ASAP)
符合POSIX,无getopt
我受到@bronson相对简单的回答的启发,并试图改进它(不增加太多复杂性)。结果如下:
使用-n[arg]、-abn[arg],--name[arg]和--name=arg样式中的任意一种选项;参数可以按任何顺序出现,循环后$@中只留下位置参数;使用--强制将剩余的参数视为位置参数;检测无效选项和缺少的参数;不依赖于getopt或外部工具(一个功能使用简单的sed命令);便携式,紧凑,可读性强,具有独立功能。
# Convenience functions.
usage_error () { echo >&2 "$(basename $0): $1"; exit 2; }
assert_argument () { test "$1" != "$EOL" || usage_error "$2 requires an argument"; }
# One loop, nothing more.
if [ "$#" != 0 ]; then
EOL=$(printf '\1\3\3\7')
set -- "$@" "$EOL"
while [ "$1" != "$EOL" ]; do
opt="$1"; shift
case "$opt" in
# Your options go here.
-f|--flag) flag='true';;
-n|--name) assert_argument "$1" "$opt"; name="$1"; shift;;
# Arguments processing. You may remove any unneeded line after the 1st.
-|''|[!-]*) set -- "$@" "$opt";; # positional argument, rotate to the end
--*=*) set -- "${opt%%=*}" "${opt#*=}" "$@";; # convert '--name=arg' to '--name' 'arg'
-[!-]?*) set -- $(echo "${opt#-}" | sed 's/\(.\)/ -\1/g') "$@";; # convert '-abc' to '-a' '-b' '-c'
--) while [ "$1" != "$EOL" ]; do set -- "$@" "$1"; shift; done;; # process remaining arguments as positional
-*) usage_error "unknown option: '$opt'";; # catch misspelled options
*) usage_error "this should NEVER happen ($opt)";; # sanity test for previous patterns
esac
done
shift # $EOL
fi
# Do something cool with "$@"... \o/
注:我知道。。。二进制模式为0x01030307的参数可能会破坏逻辑。但是,如果有人在命令行中传递这样的参数,他们应该得到它。
Bash空格分隔(例如--option参数)
cat >/tmp/demo-space-separated.sh <<'EOF'
#!/bin/bash
POSITIONAL_ARGS=()
while [[ $# -gt 0 ]]; do
case $1 in
-e|--extension)
EXTENSION="$2"
shift # past argument
shift # past value
;;
-s|--searchpath)
SEARCHPATH="$2"
shift # past argument
shift # past value
;;
--default)
DEFAULT=YES
shift # past argument
;;
-*|--*)
echo "Unknown option $1"
exit 1
;;
*)
POSITIONAL_ARGS+=("$1") # save positional arg
shift # past argument
;;
esac
done
set -- "${POSITIONAL_ARGS[@]}" # restore positional parameters
echo "FILE EXTENSION = ${EXTENSION}"
echo "SEARCH PATH = ${SEARCHPATH}"
echo "DEFAULT = ${DEFAULT}"
echo "Number files in SEARCH PATH with EXTENSION:" $(ls -1 "${SEARCHPATH}"/*."${EXTENSION}" | wc -l)
if [[ -n $1 ]]; then
echo "Last line of file specified as non-opt/last argument:"
tail -1 "$1"
fi
EOF
chmod +x /tmp/demo-space-separated.sh
/tmp/demo-space-separated.sh -e conf -s /etc /etc/hosts
复制粘贴上面的块的输出
FILE EXTENSION = conf
SEARCH PATH = /etc
DEFAULT =
Number files in SEARCH PATH with EXTENSION: 14
Last line of file specified as non-opt/last argument:
#93.184.216.34 example.com
用法
demo-space-separated.sh -e conf -s /etc /etc/hosts
Bash等于分隔符(例如,--option=argument)
cat >/tmp/demo-equals-separated.sh <<'EOF'
#!/bin/bash
for i in "$@"; do
case $i in
-e=*|--extension=*)
EXTENSION="${i#*=}"
shift # past argument=value
;;
-s=*|--searchpath=*)
SEARCHPATH="${i#*=}"
shift # past argument=value
;;
--default)
DEFAULT=YES
shift # past argument with no value
;;
-*|--*)
echo "Unknown option $i"
exit 1
;;
*)
;;
esac
done
echo "FILE EXTENSION = ${EXTENSION}"
echo "SEARCH PATH = ${SEARCHPATH}"
echo "DEFAULT = ${DEFAULT}"
echo "Number files in SEARCH PATH with EXTENSION:" $(ls -1 "${SEARCHPATH}"/*."${EXTENSION}" | wc -l)
if [[ -n $1 ]]; then
echo "Last line of file specified as non-opt/last argument:"
tail -1 $1
fi
EOF
chmod +x /tmp/demo-equals-separated.sh
/tmp/demo-equals-separated.sh -e=conf -s=/etc /etc/hosts
复制粘贴上面的块的输出
FILE EXTENSION = conf
SEARCH PATH = /etc
DEFAULT =
Number files in SEARCH PATH with EXTENSION: 14
Last line of file specified as non-opt/last argument:
#93.184.216.34 example.com
用法
demo-equals-separated.sh -e=conf -s=/etc /etc/hosts
要更好地理解${i#*=},请在本指南中搜索“Substring Removal”。它在功能上等同于调用一个不需要的子流程的‘sed’s/[^=]*=//'<<<“$i”`或调用两个不需要子流程的“echo”$i”|sed’s/[^=]*=//'`。
将bash与getopt[s]一起使用
getopt(1)限制(较旧、较新的getopt版本):
无法处理空字符串的参数无法处理带有嵌入空格的参数
最近的getopt版本没有这些限制。有关更多信息,请参阅这些文档。
POSIX获取选项
此外,POSIX外壳和其他提供的getopts没有这些限制。我包含了一个简单的getopts示例。
cat >/tmp/demo-getopts.sh <<'EOF'
#!/bin/sh
# A POSIX variable
OPTIND=1 # Reset in case getopts has been used previously in the shell.
# Initialize our own variables:
output_file=""
verbose=0
while getopts "h?vf:" opt; do
case "$opt" in
h|\?)
show_help
exit 0
;;
v) verbose=1
;;
f) output_file=$OPTARG
;;
esac
done
shift $((OPTIND-1))
[ "${1:-}" = "--" ] && shift
echo "verbose=$verbose, output_file='$output_file', Leftovers: $@"
EOF
chmod +x /tmp/demo-getopts.sh
/tmp/demo-getopts.sh -vf /etc/hosts foo bar
复制粘贴上面的块的输出
verbose=1, output_file='/etc/hosts', Leftovers: foo bar
用法
demo-getopts.sh -vf /etc/hosts foo bar
getopts的优点是:
它更便于携带,可以在其他外壳中使用,如dash。它可以以典型的Unix方式自动处理多个单一选项,如-vf文件名。
getopts的缺点是它只能处理短选项(-h,而不是-help),而无需额外代码。
有一个getopts教程,它解释了所有语法和变量的含义。在bash中,还有帮助getopts,这可能会提供信息。
while [ "$#" -gt 0 ]; do
case "$1" in
-n) name="$2"; shift 2;;
-p) pidfile="$2"; shift 2;;
-l) logfile="$2"; shift 2;;
--name=*) name="${1#*=}"; shift 1;;
--pidfile=*) pidfile="${1#*=}"; shift 1;;
--logfile=*) logfile="${1#*=}"; shift 1;;
--name|--pidfile|--logfile) echo "$1 requires an argument" >&2; exit 1;;
-*) echo "unknown option: $1" >&2; exit 1;;
*) handle_argument "$1"; shift 1;;
esac
done
此解决方案:
句柄-n arg和--name=arg允许在末尾使用参数如果有任何拼写错误,则显示正常错误兼容,不使用抨击可读,不需要在循环中维护状态
我发现在脚本中编写可移植解析的问题非常令人沮丧,因此我编写了Argbash-一个FOSS代码生成器,它可以为您的脚本生成参数解析代码,并且具有一些不错的功能:
https://argbash.io