例子:
absolute="/foo/bar"
current="/foo/baz/foo"
# Magic
relative="../../bar"
我如何创造魔法(希望不是太复杂的代码…)?
例子:
absolute="/foo/bar"
current="/foo/baz/foo"
# Magic
relative="../../bar"
我如何创造魔法(希望不是太复杂的代码…)?
当前回答
Python的os.path.relpath作为shell函数
这个relpath练习的目标是模仿xni提出的Python 2.7的os.path.relpath函数(从Python 2.6版可用,但只能在2.7中正常工作)。因此,一些结果可能与其他答案中提供的函数不同。
(我没有在路径中测试换行符,因为它破坏了基于从ZSH调用python -c的验证。经过一些努力,这当然是可能的。)
关于Bash中的“魔法”,我很久以前就放弃了在Bash中寻找魔法,但我已经在ZSH中找到了我需要的所有魔法,然后是一些。
因此,我提出了两种实现。
第一个实现的目标是完全兼容posix。我已经在Debian 6.0.6的“挤压”上用/bin/dash测试了它。它还可以在OS X 10.8.3上完美地与/bin/sh一起工作,这实际上是伪装成POSIX shell的Bash版本3.2。
第二个实现是一个ZSH shell函数,它对路径中的多个斜杠和其他麻烦具有健壮性。如果您有可用的ZSH,这是推荐的版本,即使您是在下面给出的脚本形式中调用它(即使用#!/usr/bin/env zsh)。
最后,我编写了一个ZSH脚本,根据其他答案中提供的测试用例,验证$PATH中relpath命令的输出。我通过添加一些空格、制表符和标点符号,例如!? *在这里和那里,还抛出了另一个测试与vim-powerline中发现的奇异UTF-8字符。
POSIX外壳函数
首先,posix兼容的shell函数。它适用于各种路径,但不清除多个斜杠或解析符号链接。
#!/bin/sh
relpath () {
[ $# -ge 1 ] && [ $# -le 2 ] || return 1
current="${2:+"$1"}"
target="${2:-"$1"}"
[ "$target" != . ] || target=/
target="/${target##/}"
[ "$current" != . ] || current=/
current="${current:="/"}"
current="/${current##/}"
appendix="${target##/}"
relative=''
while appendix="${target#"$current"/}"
[ "$current" != '/' ] && [ "$appendix" = "$target" ]; do
if [ "$current" = "$appendix" ]; then
relative="${relative:-.}"
echo "${relative#/}"
return 0
fi
current="${current%/*}"
relative="$relative${relative:+/}.."
done
relative="$relative${relative:+${appendix:+/}}${appendix#/}"
echo "$relative"
}
relpath "$@"
ZSH壳函数
现在是更加健壮的zsh版本。如果您希望它将参数解析为真实路径à la realpath -f(在Linux coreutils包中可用),请将第3行和第4行上的:a替换为:a。
要在zsh中使用它,请删除第一行和最后一行,并将其放在$FPATH变量中的目录中。
#!/usr/bin/env zsh
relpath () {
[[ $# -ge 1 ]] && [[ $# -le 2 ]] || return 1
local target=${${2:-$1}:a} # replace `:a' by `:A` to resolve symlinks
local current=${${${2:+$1}:-$PWD}:a} # replace `:a' by `:A` to resolve symlinks
local appendix=${target#/}
local relative=''
while appendix=${target#$current/}
[[ $current != '/' ]] && [[ $appendix = $target ]]; do
if [[ $current = $appendix ]]; then
relative=${relative:-.}
print ${relative#/}
return 0
fi
current=${current%/*}
relative="$relative${relative:+/}.."
done
relative+=${relative:+${appendix:+/}}${appendix#/}
print $relative
}
relpath "$@"
测试脚本
最后是测试脚本。它接受一个选项,即-v来启用详细输出。
#!/usr/bin/env zsh
set -eu
VERBOSE=false
script_name=$(basename $0)
usage () {
print "\n Usage: $script_name SRC_PATH DESTINATION_PATH\n" >&2
exit ${1:=1}
}
vrb () { $VERBOSE && print -P ${(%)@} || return 0; }
relpath_check () {
[[ $# -ge 1 ]] && [[ $# -le 2 ]] || return 1
target=${${2:-$1}}
prefix=${${${2:+$1}:-$PWD}}
result=$(relpath $prefix $target)
# Compare with python's os.path.relpath function
py_result=$(python -c "import os.path; print os.path.relpath('$target', '$prefix')")
col='%F{green}'
if [[ $result != $py_result ]] && col='%F{red}' || $VERBOSE; then
print -P "${col}Source: '$prefix'\nDestination: '$target'%f"
print -P "${col}relpath: ${(qq)result}%f"
print -P "${col}python: ${(qq)py_result}%f\n"
fi
}
run_checks () {
print "Running checks..."
relpath_check '/ a b/å/⮀*/!' '/ a b/å/⮀/xäå/?'
relpath_check '/' '/A'
relpath_check '/A' '/'
relpath_check '/ & / !/*/\\/E' '/'
relpath_check '/' '/ & / !/*/\\/E'
relpath_check '/ & / !/*/\\/E' '/ & / !/?/\\/E/F'
relpath_check '/X/Y' '/ & / !/C/\\/E/F'
relpath_check '/ & / !/C' '/A'
relpath_check '/A / !/C' '/A /B'
relpath_check '/Â/ !/C' '/Â/ !/C'
relpath_check '/ & /B / C' '/ & /B / C/D'
relpath_check '/ & / !/C' '/ & / !/C/\\/Ê'
relpath_check '/Å/ !/C' '/Å/ !/D'
relpath_check '/.A /*B/C' '/.A /*B/\\/E'
relpath_check '/ & / !/C' '/ & /D'
relpath_check '/ & / !/C' '/ & /\\/E'
relpath_check '/ & / !/C' '/\\/E/F'
relpath_check /home/part1/part2 /home/part1/part3
relpath_check /home/part1/part2 /home/part4/part5
relpath_check /home/part1/part2 /work/part6/part7
relpath_check /home/part1 /work/part1/part2/part3/part4
relpath_check /home /work/part2/part3
relpath_check / /work/part2/part3/part4
relpath_check /home/part1/part2 /home/part1/part2/part3/part4
relpath_check /home/part1/part2 /home/part1/part2/part3
relpath_check /home/part1/part2 /home/part1/part2
relpath_check /home/part1/part2 /home/part1
relpath_check /home/part1/part2 /home
relpath_check /home/part1/part2 /
relpath_check /home/part1/part2 /work
relpath_check /home/part1/part2 /work/part1
relpath_check /home/part1/part2 /work/part1/part2
relpath_check /home/part1/part2 /work/part1/part2/part3
relpath_check /home/part1/part2 /work/part1/part2/part3/part4
relpath_check home/part1/part2 home/part1/part3
relpath_check home/part1/part2 home/part4/part5
relpath_check home/part1/part2 work/part6/part7
relpath_check home/part1 work/part1/part2/part3/part4
relpath_check home work/part2/part3
relpath_check . work/part2/part3
relpath_check home/part1/part2 home/part1/part2/part3/part4
relpath_check home/part1/part2 home/part1/part2/part3
relpath_check home/part1/part2 home/part1/part2
relpath_check home/part1/part2 home/part1
relpath_check home/part1/part2 home
relpath_check home/part1/part2 .
relpath_check home/part1/part2 work
relpath_check home/part1/part2 work/part1
relpath_check home/part1/part2 work/part1/part2
relpath_check home/part1/part2 work/part1/part2/part3
relpath_check home/part1/part2 work/part1/part2/part3/part4
print "Done with checks."
}
if [[ $# -gt 0 ]] && [[ $1 = "-v" ]]; then
VERBOSE=true
shift
fi
if [[ $# -eq 0 ]]; then
run_checks
else
VERBOSE=true
relpath_check "$@"
fi
其他回答
Python的os.path.relpath作为shell函数
这个relpath练习的目标是模仿xni提出的Python 2.7的os.path.relpath函数(从Python 2.6版可用,但只能在2.7中正常工作)。因此,一些结果可能与其他答案中提供的函数不同。
(我没有在路径中测试换行符,因为它破坏了基于从ZSH调用python -c的验证。经过一些努力,这当然是可能的。)
关于Bash中的“魔法”,我很久以前就放弃了在Bash中寻找魔法,但我已经在ZSH中找到了我需要的所有魔法,然后是一些。
因此,我提出了两种实现。
第一个实现的目标是完全兼容posix。我已经在Debian 6.0.6的“挤压”上用/bin/dash测试了它。它还可以在OS X 10.8.3上完美地与/bin/sh一起工作,这实际上是伪装成POSIX shell的Bash版本3.2。
第二个实现是一个ZSH shell函数,它对路径中的多个斜杠和其他麻烦具有健壮性。如果您有可用的ZSH,这是推荐的版本,即使您是在下面给出的脚本形式中调用它(即使用#!/usr/bin/env zsh)。
最后,我编写了一个ZSH脚本,根据其他答案中提供的测试用例,验证$PATH中relpath命令的输出。我通过添加一些空格、制表符和标点符号,例如!? *在这里和那里,还抛出了另一个测试与vim-powerline中发现的奇异UTF-8字符。
POSIX外壳函数
首先,posix兼容的shell函数。它适用于各种路径,但不清除多个斜杠或解析符号链接。
#!/bin/sh
relpath () {
[ $# -ge 1 ] && [ $# -le 2 ] || return 1
current="${2:+"$1"}"
target="${2:-"$1"}"
[ "$target" != . ] || target=/
target="/${target##/}"
[ "$current" != . ] || current=/
current="${current:="/"}"
current="/${current##/}"
appendix="${target##/}"
relative=''
while appendix="${target#"$current"/}"
[ "$current" != '/' ] && [ "$appendix" = "$target" ]; do
if [ "$current" = "$appendix" ]; then
relative="${relative:-.}"
echo "${relative#/}"
return 0
fi
current="${current%/*}"
relative="$relative${relative:+/}.."
done
relative="$relative${relative:+${appendix:+/}}${appendix#/}"
echo "$relative"
}
relpath "$@"
ZSH壳函数
现在是更加健壮的zsh版本。如果您希望它将参数解析为真实路径à la realpath -f(在Linux coreutils包中可用),请将第3行和第4行上的:a替换为:a。
要在zsh中使用它,请删除第一行和最后一行,并将其放在$FPATH变量中的目录中。
#!/usr/bin/env zsh
relpath () {
[[ $# -ge 1 ]] && [[ $# -le 2 ]] || return 1
local target=${${2:-$1}:a} # replace `:a' by `:A` to resolve symlinks
local current=${${${2:+$1}:-$PWD}:a} # replace `:a' by `:A` to resolve symlinks
local appendix=${target#/}
local relative=''
while appendix=${target#$current/}
[[ $current != '/' ]] && [[ $appendix = $target ]]; do
if [[ $current = $appendix ]]; then
relative=${relative:-.}
print ${relative#/}
return 0
fi
current=${current%/*}
relative="$relative${relative:+/}.."
done
relative+=${relative:+${appendix:+/}}${appendix#/}
print $relative
}
relpath "$@"
测试脚本
最后是测试脚本。它接受一个选项,即-v来启用详细输出。
#!/usr/bin/env zsh
set -eu
VERBOSE=false
script_name=$(basename $0)
usage () {
print "\n Usage: $script_name SRC_PATH DESTINATION_PATH\n" >&2
exit ${1:=1}
}
vrb () { $VERBOSE && print -P ${(%)@} || return 0; }
relpath_check () {
[[ $# -ge 1 ]] && [[ $# -le 2 ]] || return 1
target=${${2:-$1}}
prefix=${${${2:+$1}:-$PWD}}
result=$(relpath $prefix $target)
# Compare with python's os.path.relpath function
py_result=$(python -c "import os.path; print os.path.relpath('$target', '$prefix')")
col='%F{green}'
if [[ $result != $py_result ]] && col='%F{red}' || $VERBOSE; then
print -P "${col}Source: '$prefix'\nDestination: '$target'%f"
print -P "${col}relpath: ${(qq)result}%f"
print -P "${col}python: ${(qq)py_result}%f\n"
fi
}
run_checks () {
print "Running checks..."
relpath_check '/ a b/å/⮀*/!' '/ a b/å/⮀/xäå/?'
relpath_check '/' '/A'
relpath_check '/A' '/'
relpath_check '/ & / !/*/\\/E' '/'
relpath_check '/' '/ & / !/*/\\/E'
relpath_check '/ & / !/*/\\/E' '/ & / !/?/\\/E/F'
relpath_check '/X/Y' '/ & / !/C/\\/E/F'
relpath_check '/ & / !/C' '/A'
relpath_check '/A / !/C' '/A /B'
relpath_check '/Â/ !/C' '/Â/ !/C'
relpath_check '/ & /B / C' '/ & /B / C/D'
relpath_check '/ & / !/C' '/ & / !/C/\\/Ê'
relpath_check '/Å/ !/C' '/Å/ !/D'
relpath_check '/.A /*B/C' '/.A /*B/\\/E'
relpath_check '/ & / !/C' '/ & /D'
relpath_check '/ & / !/C' '/ & /\\/E'
relpath_check '/ & / !/C' '/\\/E/F'
relpath_check /home/part1/part2 /home/part1/part3
relpath_check /home/part1/part2 /home/part4/part5
relpath_check /home/part1/part2 /work/part6/part7
relpath_check /home/part1 /work/part1/part2/part3/part4
relpath_check /home /work/part2/part3
relpath_check / /work/part2/part3/part4
relpath_check /home/part1/part2 /home/part1/part2/part3/part4
relpath_check /home/part1/part2 /home/part1/part2/part3
relpath_check /home/part1/part2 /home/part1/part2
relpath_check /home/part1/part2 /home/part1
relpath_check /home/part1/part2 /home
relpath_check /home/part1/part2 /
relpath_check /home/part1/part2 /work
relpath_check /home/part1/part2 /work/part1
relpath_check /home/part1/part2 /work/part1/part2
relpath_check /home/part1/part2 /work/part1/part2/part3
relpath_check /home/part1/part2 /work/part1/part2/part3/part4
relpath_check home/part1/part2 home/part1/part3
relpath_check home/part1/part2 home/part4/part5
relpath_check home/part1/part2 work/part6/part7
relpath_check home/part1 work/part1/part2/part3/part4
relpath_check home work/part2/part3
relpath_check . work/part2/part3
relpath_check home/part1/part2 home/part1/part2/part3/part4
relpath_check home/part1/part2 home/part1/part2/part3
relpath_check home/part1/part2 home/part1/part2
relpath_check home/part1/part2 home/part1
relpath_check home/part1/part2 home
relpath_check home/part1/part2 .
relpath_check home/part1/part2 work
relpath_check home/part1/part2 work/part1
relpath_check home/part1/part2 work/part1/part2
relpath_check home/part1/part2 work/part1/part2/part3
relpath_check home/part1/part2 work/part1/part2/part3/part4
print "Done with checks."
}
if [[ $# -gt 0 ]] && [[ $1 = "-v" ]]; then
VERBOSE=true
shift
fi
if [[ $# -eq 0 ]]; then
run_checks
else
VERBOSE=true
relpath_check "$@"
fi
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"
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 $relative
test.sh:
#!/bin/bash
cd /home/ubuntu
touch blah
TEST=/home/ubuntu/.//blah
echo TEST=$TEST
TMP=$(readlink -e "$TEST")
echo TMP=$TMP
REL=${TMP#$(pwd)/}
echo REL=$REL
测试:
$ ./test.sh
TEST=/home/ubuntu/.//blah
TMP=/home/ubuntu/blah
REL=blah
这里的答案并不是每天都能用的。由于在纯bash中很难正确地做到这一点,我建议以下可靠的解决方案(类似于注释中的一个建议):
function relpath() {
python -c "import os,sys;print(os.path.relpath(*(sys.argv[1:])))" "$@";
}
然后,你可以得到基于当前目录的相对路径:
echo $(relpath somepath)
或者你可以指定路径相对于给定的目录:
echo $(relpath somepath /etc) # relative to /etc
一个缺点是这需要python,但是:
它在任何python >= 2.6中工作相同 它不要求文件或目录存在。 文件名可以包含更广泛的特殊字符。 例如,如果文件名包含 空格或其他特殊字符。 它是一个单行函数,不会使脚本混乱。
注意,包含basename或dirname的解决方案不一定更好,因为它们要求安装coreutils。如果有人有可靠而简单的纯bash解决方案(而不是令人费解的好奇心),我会感到惊讶。