是否有办法在bash上比较这些字符串,例如:2.4.5和2.8和2.4.5.1?


当前回答

感谢Dennis的解决方案,我们可以扩展它以允许比较运算符'>','<','=','==','<='和'>='。

# compver ver1 '=|==|>|<|>=|<=' ver2
compver() { 
    local op
    vercomp $1 $3
    case $? in
        0) op='=';;
        1) op='>';;
        2) op='<';;
    esac
    [[ $2 == *$op* ]] && return 0 || return 1
}

然后我们可以在表达式中使用比较运算符,比如:

compver 1.7 '<=' 1.8
compver 1.7 '==' 1.7
compver 1.7 '=' 1.7

并且只测试结果的真/假,比如:

if compver $ver1 '>' $ver2; then
    echo "Newer"
fi

其他回答

这里是另一个没有任何外部调用的纯bash解决方案:

#!/bin/bash

function version_compare {

IFS='.' read -ra ver1 <<< "$1"
IFS='.' read -ra ver2 <<< "$2"

[[ ${#ver1[@]} -gt ${#ver2[@]} ]] && till=${#ver1[@]} || till=${#ver2[@]}

for ((i=0; i<${till}; i++)); do

    local num1; local num2;

    [[ -z ${ver1[i]} ]] && num1=0 || num1=${ver1[i]}
    [[ -z ${ver2[i]} ]] && num2=0 || num2=${ver2[i]}

    if [[ $num1 -gt $num2 ]]; then
        echo ">"; return 0
    elif
       [[ $num1 -lt $num2 ]]; then
        echo "<"; return 0
    fi
done

echo "="; return 0
}

echo "${1} $(version_compare "${1}" "${2}") ${2}"

还有更简单的解决方案,如果你确定所讨论的版本在第一个点后不包含前导零:

#!/bin/bash

function version_compare {

local ver1=${1//.}
local ver2=${2//.}


    if [[ $ver1 -gt $ver2 ]]; then
        echo ">"; return 0
    elif    
       [[ $ver1 -lt $ver2 ]]; then
        echo "<"; return 0
    fi 

echo "="; return 0
}

echo "${1} $(version_compare "${1}" "${2}") ${2}"

这适用于像1.2.3 vs 1.3.1 vs 0.9.7这样的版本,但不适用于其他版本 1.2.3 vs 1.2.3.0或1.01.1 vs 1.1.1

下面是一个不使用外部命令的简单Bash函数。它适用于包含最多三个数字部分的版本字符串-小于3也是可以的。它可以很容易地扩展为更多。它实现了=、<、<=、>、>=和!=条件。

#!/bin/bash
vercmp() {
    version1=$1 version2=$2 condition=$3

    IFS=. v1_array=($version1) v2_array=($version2)
    v1=$((v1_array[0] * 100 + v1_array[1] * 10 + v1_array[2]))
    v2=$((v2_array[0] * 100 + v2_array[1] * 10 + v2_array[2]))
    diff=$((v2 - v1))
    [[ $condition = '='  ]] && ((diff == 0)) && return 0
    [[ $condition = '!=' ]] && ((diff != 0)) && return 0
    [[ $condition = '<'  ]] && ((diff >  0)) && return 0
    [[ $condition = '<=' ]] && ((diff >= 0)) && return 0
    [[ $condition = '>'  ]] && ((diff <  0)) && return 0
    [[ $condition = '>=' ]] && ((diff <= 0)) && return 0
    return 1
}

下面是测试:

for tv1 in '*' 1.1.1 2.5.3 7.3.0 0.5.7 10.3.9 8.55.32 0.0.1; do
    for tv2 in 3.1.1 1.5.3 4.3.0 0.0.7 0.3.9 11.55.32 10.0.0 '*'; do
      for c in '=' '>' '<' '>=' '<=' '!='; do
        vercmp "$tv1" "$tv2" "$c" && printf '%s\n' "$tv1 $c $tv2 is true" || printf '%s\n' "$tv1 $c $tv2 is false"
      done
    done
done

测试输出的子集:

<snip>

* >= * is true
* <= * is true
* != * is true
1.1.1 = 3.1.1 is false
1.1.1 > 3.1.1 is false
1.1.1 < 3.1.1 is true
1.1.1 >= 3.1.1 is false
1.1.1 <= 3.1.1 is true
1.1.1 != 3.1.1 is true
1.1.1 = 1.5.3 is false
1.1.1 > 1.5.3 is false
1.1.1 < 1.5.3 is true
1.1.1 >= 1.5.3 is false
1.1.1 <= 1.5.3 is true
1.1.1 != 1.5.3 is true
1.1.1 = 4.3.0 is false
1.1.1 > 4.3.0 is false

<snip>

这在版本中最多为4个字段。

$ function ver { printf "%03d%03d%03d%03d" $(echo "$1" | tr '.' ' '); }
$ [ $(ver 10.9) -lt $(ver 10.10) ] && echo hello  
hello

下面是对顶部答案(Dennis的)的改进,它更简洁,并使用了不同的返回值方案,以便通过单个比较轻松实现<=和>=。它还比较不是[0-9]的第一个字符之后的所有内容。]因此1.0rc1 < 1.0rc2。

# Compares two tuple-based, dot-delimited version numbers a and b (possibly
# with arbitrary string suffixes). Returns:
# 1 if a<b
# 2 if equal
# 3 if a>b
# Everything after the first character not in [0-9.] is compared
# lexicographically using ASCII ordering if the tuple-based versions are equal.
compare_versions() {
    if [[ $1 == "$2" ]]; then
        return 2
    fi
    local IFS=.
    local i a=(${1%%[^0-9.]*}) b=(${2%%[^0-9.]*})
    local arem=${1#${1%%[^0-9.]*}} brem=${2#${2%%[^0-9.]*}}
    for ((i=0; i<${#a[@]} || i<${#b[@]}; i++)); do
        if ((10#${a[i]:-0} < 10#${b[i]:-0})); then
            return 1
        elif ((10#${a[i]:-0} > 10#${b[i]:-0})); then
            return 3
        fi
    done
    if [ "$arem" '<' "$brem" ]; then
        return 1
    elif [ "$arem" '>' "$brem" ]; then
        return 3
    fi
    return 2
}

为了解决@gammazero的评论,一个(我认为)与语义版本兼容的更长的版本是:

# Compares two dot-delimited decimal-element version numbers a and b that may
# also have arbitrary string suffixes. Compatible with semantic versioning, but
# not as strict: comparisons of non-semver strings may have unexpected
# behavior.
#
# Returns:
# 1 if a<b
# 2 if equal
# 3 if a>b
compare_versions() {
    local LC_ALL=C

    # Optimization
    if [[ $1 == "$2" ]]; then
        return 2
    fi

    # Compare numeric release versions. Supports an arbitrary number of numeric
    # elements (i.e., not just X.Y.Z) in which unspecified indices are regarded
    # as 0.
    local aver=${1%%[^0-9.]*} bver=${2%%[^0-9.]*}
    local arem=${1#$aver} brem=${2#$bver}
    local IFS=.
    local i a=($aver) b=($bver)
    for ((i=0; i<${#a[@]} || i<${#b[@]}; i++)); do
        if ((10#${a[i]:-0} < 10#${b[i]:-0})); then
            return 1
        elif ((10#${a[i]:-0} > 10#${b[i]:-0})); then
            return 3
        fi
    done

    # Remove build metadata before remaining comparison
    arem=${arem%%+*}
    brem=${brem%%+*}

    # Prelease (w/remainder) always older than release (no remainder)
    if [ -n "$arem" -a -z "$brem" ]; then
        return 1
    elif [ -z "$arem" -a -n "$brem" ]; then
        return 3
    fi

    # Otherwise, split by periods and compare individual elements either
    # numerically or lexicographically
    local a=(${arem#-}) b=(${brem#-})
    for ((i=0; i<${#a[@]} && i<${#b[@]}; i++)); do
        local anns=${a[i]#${a[i]%%[^0-9]*}} bnns=${b[i]#${b[i]%%[^0-9]*}}
        if [ -z "$anns$bnns" ]; then
            # Both numeric
            if ((10#${a[i]:-0} < 10#${b[i]:-0})); then
                return 1
            elif ((10#${a[i]:-0} > 10#${b[i]:-0})); then
                return 3
            fi
        elif [ -z "$anns" ]; then
            # Numeric comes before non-numeric
            return 1
        elif [ -z "$bnns" ]; then
            # Numeric comes before non-numeric
            return 3
        else
            # Compare lexicographically
            if [[ ${a[i]} < ${b[i]} ]]; then
                return 1
            elif [[ ${a[i]} > ${b[i]} ]]; then
                return 3
            fi
        fi
    done

    # Fewer elements is earlier
    if (( ${#a[@]} < ${#b[@]} )); then
        return 1
    elif (( ${#a[@]} > ${#b[@]} )); then
        return 3
    fi

    # Must be equal!
    return 2
}

可能没有普遍正确的方法来实现这一点。如果您正在尝试比较Debian包系统中的版本,请尝试dpkg——compare-versions <first> <relation> <second>。