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
我实现了一个函数,返回与Dennis Williamson相同的结果,但使用更少的行数。它最初执行一个健全性检查,导致1..0从他的测试中失败(我认为应该是这样),但他所有的其他测试都通过了这段代码:
#!/bin/bash
version_compare() {
if [[ $1 =~ ^([0-9]+\.?)+$ && $2 =~ ^([0-9]+\.?)+$ ]]; then
local l=(${1//./ }) r=(${2//./ }) s=${#l[@]}; [[ ${#r[@]} -gt ${#l[@]} ]] && s=${#r[@]}
for i in $(seq 0 $((s - 1))); do
[[ ${l[$i]} -gt ${r[$i]} ]] && return 1
[[ ${l[$i]} -lt ${r[$i]} ]] && return 2
done
return 0
else
echo "Invalid version number given"
exit 1
fi
}
其他回答
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
}
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
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
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")" ]
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//./ }
}