假设您已经安装了:bash、pwd、dirname、echo;relpath是

#!/bin/bash
s=$(cd ${1%%/};pwd); d=$(cd $2;pwd); b=; while [ "${d#$s/}" == "${d}" ]
do s=$(dirname $s);b="../${b}"; done; echo ${b}${d#$s/}

我从pini和其他一些想法中得到了答案

注意:这要求两个路径都是现有文件夹。文件将无法工作。

我把你的问题作为一个挑战，用“可移植的”shell代码来编写它，即。

考虑到POSIX外壳 没有数组之类的bashisms 避免像打瘟疫一样打外部电话。脚本中没有一个分叉!这使得它非常快，特别是在有显著分叉开销的系统上，比如cygwin。 必须处理路径名中的glob字符(*，?，[，])

它运行在任何POSIX兼容shell (zsh, bash, ksh, ash, busybox，…)上。它甚至包含一个测试套件来验证其操作。路径名的规范化留作练习。: -)

#!/bin/sh

# Find common parent directory path for a pair of paths.
# Call with two pathnames as args, e.g.
# commondirpart foo/bar foo/baz/bat -> result="foo/"
# The result is either empty or ends with "/".
commondirpart () {
   result=""
   while test ${#1} -gt 0 -a ${#2} -gt 0; do
      if test "${1%${1#?}}" != "${2%${2#?}}"; then   # First characters the same?
         break                                       # No, we're done comparing.
      fi
      result="$result${1%${1#?}}"                    # Yes, append to result.
      set -- "${1#?}" "${2#?}"                       # Chop first char off both strings.
   done
   case "$result" in
   (""|*/) ;;
   (*)     result="${result%/*}/";;
   esac
}

# Turn foo/bar/baz into ../../..
#
dir2dotdot () {
   OLDIFS="$IFS" IFS="/" result=""
   for dir in $1; do
      result="$result../"
   done
   result="${result%/}"
   IFS="$OLDIFS"
}

# Call with FROM TO args.
relativepath () {
   case "$1" in
   (*//*|*/./*|*/../*|*?/|*/.|*/..)
      printf '%s\n' "'$1' not canonical"; exit 1;;
   (/*)
      from="${1#?}";;
   (*)
      printf '%s\n' "'$1' not absolute"; exit 1;;
   esac
   case "$2" in
   (*//*|*/./*|*/../*|*?/|*/.|*/..)
      printf '%s\n' "'$2' not canonical"; exit 1;;
   (/*)
      to="${2#?}";;
   (*)
      printf '%s\n' "'$2' not absolute"; exit 1;;
   esac

   case "$to" in
   ("$from")   # Identical directories.
      result=".";;
   ("$from"/*) # From /x to /x/foo/bar -> foo/bar
      result="${to##$from/}";;
   ("")        # From /foo/bar to / -> ../..
      dir2dotdot "$from";;
   (*)
      case "$from" in
      ("$to"/*)       # From /x/foo/bar to /x -> ../..
         dir2dotdot "${from##$to/}";;
      (*)             # Everything else.
         commondirpart "$from" "$to"
         common="$result"
         dir2dotdot "${from#$common}"
         result="$result/${to#$common}"
      esac
      ;;
   esac
}

set -f # noglob

set -x
cat <<EOF |
/ / .
/- /- .
/? /? .
/?? /?? .
/??? /??? .
/?* /?* .
/* /* .
/* /** ../**
/* /*** ../***
/*.* /*.** ../*.**
/*.??? /*.?? ../*.??
/[] /[] .
/[a-z]* /[0-9]* ../[0-9]*
/foo /foo .
/foo / ..
/foo/bar / ../..
/foo/bar /foo ..
/foo/bar /foo/baz ../baz
/foo/bar /bar/foo  ../../bar/foo
/foo/bar/baz /gnarf/blurfl/blubb ../../../gnarf/blurfl/blubb
/foo/bar/baz /gnarf ../../../gnarf
/foo/bar/baz /foo/baz ../../baz
/foo. /bar. ../bar.
EOF
while read FROM TO VIA; do
   relativepath "$FROM" "$TO"
   printf '%s\n' "FROM: $FROM" "TO:   $TO" "VIA:  $result"
   if test "$result" != "$VIA"; then
      printf '%s\n' "OOOPS! Expected '$VIA' but got '$result'"
   fi
done

# vi: set tabstop=3 shiftwidth=3 expandtab fileformat=unix :

kasku和Pini的答案略有改进，空格更好，允许传递相对路径:

#!/bin/bash
# both $1 and $2 are paths
# returns $2 relative to $1
absolute=`readlink -f "$2"`
current=`readlink -f "$1"`
# Perl is magic
# Quoting horror.... spaces cause problems, that's why we need the extra " in here:
relative=$(perl -MFile::Spec -e "print File::Spec->abs2rel(q($absolute),q($current))")

echo $relative

我需要这样的东西，但它也解决了符号链接。我发现pwd有一个-P标志用于此目的。附加了我的脚本的一个片段。它在shell脚本的函数中，因此是$1和$2。结果值是从START_ABS到END_ABS的相对路径，位于UPDIRS变量中。为了执行pwd -P，将脚本cd放入每个参数目录，这也意味着将处理相对路径参数。干杯,吉姆

SAVE_DIR="$PWD"
cd "$1"
START_ABS=`pwd -P`
cd "$SAVE_DIR"
cd "$2"
END_ABS=`pwd -P`

START_WORK="$START_ABS"
UPDIRS=""

while test -n "${START_WORK}" -a "${END_ABS/#${START_WORK}}" '==' "$END_ABS";
do
    START_WORK=`dirname "$START_WORK"`"/"
    UPDIRS=${UPDIRS}"../"
done
UPDIRS="$UPDIRS${END_ABS/#${START_WORK}}"
cd "$SAVE_DIR"

我的解决方案:

computeRelativePath() 
{

    Source=$(readlink -f ${1})
    Target=$(readlink -f ${2})

    local OLDIFS=$IFS
    IFS="/"

    local SourceDirectoryArray=($Source)
    local TargetDirectoryArray=($Target)

    local SourceArrayLength=$(echo ${SourceDirectoryArray[@]} | wc -w)
    local TargetArrayLength=$(echo ${TargetDirectoryArray[@]} | wc -w)

    local Length
    test $SourceArrayLength -gt $TargetArrayLength && Length=$SourceArrayLength || Length=$TargetArrayLength


    local Result=""
    local AppendToEnd=""

    IFS=$OLDIFS

    local i

    for ((i = 0; i <= $Length + 1 ; i++ ))
    do
            if [ "${SourceDirectoryArray[$i]}" = "${TargetDirectoryArray[$i]}" ]
            then
                continue    
            elif [ "${SourceDirectoryArray[$i]}" != "" ] && [ "${TargetDirectoryArray[$i]}" != "" ] 
            then
                AppendToEnd="${AppendToEnd}${TargetDirectoryArray[${i}]}/"
                Result="${Result}../"               

            elif [ "${SourceDirectoryArray[$i]}" = "" ]
            then
                Result="${Result}${TargetDirectoryArray[${i}]}/"
            else
                Result="${Result}../"
            fi
    done

    Result="${Result}${AppendToEnd}"

    echo $Result

}

该脚本仅对绝对路径或没有绝对路径的相对路径的输入提供正确的结果。或者. .:

#!/bin/bash

# usage: relpath from to

if [[ "$1" == "$2" ]]
then
    echo "."
    exit
fi

IFS="/"

current=($1)
absolute=($2)

abssize=${#absolute[@]}
cursize=${#current[@]}

while [[ ${absolute[level]} == ${current[level]} ]]
do
    (( level++ ))
    if (( level > abssize || level > cursize ))
    then
        break
    fi
done

for ((i = level; i < cursize; i++))
do
    if ((i > level))
    then
        newpath=$newpath"/"
    fi
    newpath=$newpath".."
done

for ((i = level; i < abssize; i++))
do
    if [[ -n $newpath ]]
    then
        newpath=$newpath"/"
    fi
    newpath=$newpath${absolute[i]}
done

echo "$newpath"