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

如果你有coreutils-7 (Ubuntu Karmic,而不是Jaunty),那么你的排序命令应该有一个-V选项(版本排序),你可以使用它来进行比较:

verlte() {
    [  "$1" = "`echo -e "$1\n$2" | sort -V | head -n1`" ]
}

verlt() {
    [ "$1" = "$2" ] && return 1 || verlte $1 $2
}

verlte 2.5.7 2.5.6 && echo "yes" || echo "no" # no
verlt 2.4.10 2.4.9 && echo "yes" || echo "no" # no
verlt 2.4.8 2.4.10 && echo "yes" || echo "no" # yes
verlte 2.5.6 2.5.6 && echo "yes" || echo "no" # yes
verlt 2.5.6 2.5.6 && echo "yes" || echo "no" # no

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

我使用嵌入式Linux (Yocto)与BusyBox。BusyBox排序没有-V选项(但BusyBox expr匹配可以做正则表达式)。所以我需要一个Bash版本的比较,它适用于这个约束。

我做了以下(类似于Dennis Williamson的回答)来比较使用“自然排序”类型的算法。它将字符串分成数字部分和非数字部分;它以数字方式比较数字部分(因此10大于9),并以纯ASCII方式比较非数字部分。

ascii_frag() {
    expr match "$1" "\([^[:digit:]]*\)"
}

ascii_remainder() {
    expr match "$1" "[^[:digit:]]*\(.*\)"
}

numeric_frag() {
    expr match "$1" "\([[:digit:]]*\)"
}

numeric_remainder() {
    expr match "$1" "[[:digit:]]*\(.*\)"
}

vercomp_debug() {
    OUT="$1"
    #echo "${OUT}"
}

# return 1 for $1 > $2
# return 2 for $1 < $2
# return 0 for equal
vercomp() {
    local WORK1="$1"
    local WORK2="$2"
    local NUM1="", NUM2="", ASCII1="", ASCII2=""
    while true; do
        vercomp_debug "ASCII compare"
        ASCII1=`ascii_frag "${WORK1}"`
        ASCII2=`ascii_frag "${WORK2}"`
        WORK1=`ascii_remainder "${WORK1}"`
        WORK2=`ascii_remainder "${WORK2}"`
        vercomp_debug "\"${ASCII1}\" remainder \"${WORK1}\""
        vercomp_debug "\"${ASCII2}\" remainder \"${WORK2}\""

        if [ "${ASCII1}" \> "${ASCII2}" ]; then
            vercomp_debug "ascii ${ASCII1} > ${ASCII2}"
            return 1
        elif [ "${ASCII1}" \< "${ASCII2}" ]; then
            vercomp_debug "ascii ${ASCII1} < ${ASCII2}"
            return 2
        fi
        vercomp_debug "--------"

        vercomp_debug "Numeric compare"
        NUM1=`numeric_frag "${WORK1}"`
        NUM2=`numeric_frag "${WORK2}"`
        WORK1=`numeric_remainder "${WORK1}"`
        WORK2=`numeric_remainder "${WORK2}"`
        vercomp_debug "\"${NUM1}\" remainder \"${WORK1}\""
        vercomp_debug "\"${NUM2}\" remainder \"${WORK2}\""

        if [ -z "${NUM1}" -a -z "${NUM2}" ]; then
            vercomp_debug "blank 1 and blank 2 equal"
            return 0
        elif [ -z "${NUM1}" -a -n "${NUM2}" ]; then
            vercomp_debug "blank 1 less than non-blank 2"
            return 2
        elif [ -n "${NUM1}" -a -z "${NUM2}" ]; then
            vercomp_debug "non-blank 1 greater than blank 2"
            return 1
        fi

        if [ "${NUM1}" -gt "${NUM2}" ]; then
            vercomp_debug "num ${NUM1} > ${NUM2}"
            return 1
        elif [ "${NUM1}" -lt "${NUM2}" ]; then
            vercomp_debug "num ${NUM1} < ${NUM2}"
            return 2
        fi
        vercomp_debug "--------"
    done
}

它可以比较更复杂的版本号,例如

1.2-r3和1.2-r4 1.2 r3 vs 1.2r4

请注意,对于Dennis Williamson的回答中的一些极端情况,它不会返回相同的结果。特别是:

1            1.0          <
1.0          1            >
1.0.2.0      1.0.2        >
1..0         1.0          >
1.0          1..0         <

但这些都是极端情况,我认为结果仍然是合理的。

这里一个有用的技巧是字符串索引。

$ echo "${BASH_VERSION}"
4.4.23(1)-release

$ echo "${BASH_VERSION:0:1}"
4

如果它只是想知道一个版本是否比另一个版本低,我会检查sort——version-sort是否会改变我的版本字符串的顺序:

    string="$1
$2"
    [ "$string" == "$(sort --version-sort <<< "$string")" ]

我使用一个函数来规范化这些数字,然后比较它们。

for循环用于将版本字符串中的八进制数转换为十进制数,例如:1.08→1 8,1.0030→1 30,2021-02-03→2021 2 3…

(用bash 5.0.17测试

#!/usr/bin/env bash

v() {
  printf "%04d%04d%04d%04d%04d" $(for i in ${1//[^0-9]/ }; do printf "%d " $((10#$i)); done)
}

while read -r test; do
  set -- $test
  printf "$test    "
  eval "if [[ $(v $1) $3 $(v $2) ]] ; then echo true; else echo false; fi"
done << EOF
1              1                   ==
2.1            2.2                  <
3.0.4.10       3.0.4.2              >
4.08           4.08.01              <
3.2.1.9.8144   3.2                  >
3.2            3.2.1.9.8144         <
1.2            2.1                  <
2.1            1.2                  >
5.6.7          5.6.7               ==
1.01.1         1.1.1               ==
1.1.1          1.01.1              ==
1              1.0                 ==
1.0            1                   ==
1.0.2.0        1.0.2               ==
1..0           1.0                 ==
1.0            1..0                ==
1              1                    >
1.2.3~rc2      1.2.3~rc4            >
1.2.3~rc2      1.2.3~rc4           ==
1.2.3~rc2      1.2.3~rc4            <
1.2.3~rc2      1.2.3~rc4           !=
1.2.3~rc2      1.2.3+rc4            <
2021-11-23-rc1 2021-11-23-rc1.1     <
2021-11-23-rc1 2021-11-23-rc1-rf1   <
2021-01-03-rc1 2021-01-04           <
5.0.17(1)-release 5.0.17(2)-release <
EOF

结果:

1              1                   ==    true
2.1            2.2                  <    true
3.0.4.10       3.0.4.2              >    true
4.08           4.08.01              <    true
3.2.1.9.8144   3.2                  >    true
3.2            3.2.1.9.8144         <    true
1.2            2.1                  <    true
2.1            1.2                  >    true
5.6.7          5.6.7               ==    true
1.01.1         1.1.1               ==    true
1.1.1          1.01.1              ==    true
1              1.0                 ==    true
1.0            1                   ==    true
1.0.2.0        1.0.2               ==    true
1..0           1.0                 ==    true
1.0            1..0                ==    true
1              1                    >    false
1.2.3~rc2      1.2.3~rc4            >    false
1.2.3~rc2      1.2.3~rc4           ==    false
1.2.3~rc2      1.2.3~rc4            <    true
1.2.3~rc2      1.2.3~rc4           !=    true
1.2.3~rc2      1.2.3+rc4            <    true
2021-11-23-rc1 2021-11-23-rc1.1     <    true
2021-11-23-rc1 2021-11-23-rc1-rf1   <    true
2021-01-03-rc1 2021-01-04           <    true
5.0.17(1)-release 5.0.17(2)-release <    true