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

这也是一个纯bash解决方案,因为printf是bash内置的。

function ver()
# Description: use for comparisons of version strings.
# $1  : a version string of form 1.2.3.4
# use: (( $(ver 1.2.3.4) >= $(ver 1.2.3.3) )) && echo "yes" || echo "no"
{
    printf "%02d%02d%02d%02d" ${1//./ }
}

其他回答

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

这里有一个支持修订的纯Bash解决方案(例如。“1.0-r1”),答案是基于丹尼斯·威廉姆森(Dennis Williamson)发布的答案。可以很容易地修改它以支持'-RC1'之类的东西,或者通过更改正则表达式从更复杂的字符串中提取版本。

有关实现的详细信息,请参考代码内注释和/或启用包含的调试代码:

#!/bin/bash

# Compare two version strings [$1: version string 1 (v1), $2: version string 2 (v2)]
# Return values:
#   0: v1 == v2
#   1: v1 > v2
#   2: v1 < v2
# Based on: https://stackoverflow.com/a/4025065 by Dennis Williamson
function compare_versions() {

    # Trivial v1 == v2 test based on string comparison
    [[ "$1" == "$2" ]] && return 0

    # Local variables
    local regex="^(.*)-r([0-9]*)$" va1=() vr1=0 va2=() vr2=0 len i IFS="."

    # Split version strings into arrays, extract trailing revisions
    if [[ "$1" =~ ${regex} ]]; then
        va1=(${BASH_REMATCH[1]})
        [[ -n "${BASH_REMATCH[2]}" ]] && vr1=${BASH_REMATCH[2]}
    else
        va1=($1)
    fi
    if [[ "$2" =~ ${regex} ]]; then
        va2=(${BASH_REMATCH[1]})
        [[ -n "${BASH_REMATCH[2]}" ]] && vr2=${BASH_REMATCH[2]}
    else
        va2=($2)
    fi

    # Bring va1 and va2 to same length by filling empty fields with zeros
    (( ${#va1[@]} > ${#va2[@]} )) && len=${#va1[@]} || len=${#va2[@]}
    for ((i=0; i < len; ++i)); do
        [[ -z "${va1[i]}" ]] && va1[i]="0"
        [[ -z "${va2[i]}" ]] && va2[i]="0"
    done

    # Append revisions, increment length
    va1+=($vr1)
    va2+=($vr2)
    len=$((len+1))

    # *** DEBUG ***
    #echo "TEST: '${va1[@]} (?) ${va2[@]}'"

    # Compare version elements, check if v1 > v2 or v1 < v2
    for ((i=0; i < len; ++i)); do
        if (( 10#${va1[i]} > 10#${va2[i]} )); then
            return 1
        elif (( 10#${va1[i]} < 10#${va2[i]} )); then
            return 2
        fi
    done

    # All elements are equal, thus v1 == v2
    return 0
}


# ---------- everything below this line is just for testing ----------


# Test compare_versions [$1: version string 1, $2: version string 2, $3: expected result]
function test_compare_versions() {
    local op
    compare_versions "$1" "$2"
    case $? in
        0) op="==" ;;
        1) op=">" ;;
        2) op="<" ;;
    esac
    if [[ "$op" == "$3" ]]; then
        echo -e "\e[1;32mPASS: '$1 $op $2'\e[0m"
    else
        echo -e "\e[1;31mFAIL: '$1 $3 $2' (result: '$1 $op $2')\e[0m"
    fi
}

echo -e "\nThe following tests should pass:"
while read -r test; do
    test_compare_versions $test
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         ==
1.0-r1       1.0-r3       <
1.0-r9       2.0          <
3.0-r15      3.0-r9       >
...-r1       ...-r2       <
2.0-r1       1.9.8.21-r2  >
1.0          3.8.9.32-r   <
-r           -r3          <
-r3          -r           >
-r3          -r3          ==
-r           -r           ==
0.0-r2       0.0.0.0-r2   ==
1.0.0.0-r2   1.0-r2       ==
0.0.0.1-r7   -r9          >
0.0-r0       0            ==
1.002.0-r6   1.2.0-r7     <
001.001-r2   1.1-r2       ==
5.6.1-r0     5.6.1        ==
EOF

echo -e "\nThe following tests should fail:"
while read -r test; do
    test_compare_versions $test
done << EOF
1            1            >
3.0.5-r5     3..5-r5      >
4.9.21-r3    4.8.22-r9    <
1.0-r        1.0-r1       ==
-r           1.0-r        >
-r1          0.0-r1       <
-r2          0-r2         <
EOF

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")" ]
### the answer is does we second argument is higher
function _ver_higher {
        ver=`echo -ne "$1\n$2" |sort -Vr |head -n1`
        if [ "$2" == "$1" ]; then
                return 1
        elif [ "$2" == "$ver" ]; then
                return 0
        else
                return 1
        fi
}

if _ver_higher $1 $2; then
        echo higher
else
        echo same or less
fi

它非常简单和小。

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