关于macos：OS X的Bash脚本绝对路径

Bash script absolute path with OS X

我正在尝试获取OS X上当前运行脚本的绝对路径。

我看到很多回复都是针对readlink -f $0。然而，由于OSX的readlink与BSD的相同，它只是不起作用(它与GNU的版本一起工作)。

有现成的解决方案吗？

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这三个简单步骤将解决这一问题和许多其他OS X问题：

安装自制

brew install coreutils

grealpath .

(3)可改为仅realpath，见(2)输出

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有一个realpath()c函数可以完成这项工作，但在命令行上没有看到任何可用的功能。这里有一个快速而肮脏的替代品：

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#!/bin/bash

realpath() {
[[ $1 = /* ]] && echo"$1" || echo"$PWD/${1#./}"
}

realpath"$0"

如果路径以/开头，则会逐字打印路径。如果不是，它必须是一个相对路径，因此它会将$PWD提前到前面。#./部分从$1前部剥离./。

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呃。我发现之前的答案有点欠缺，原因有几个：特别是，它们不能解析多个层次的符号链接，而且它们是非常"bash-y"。虽然最初的问题确实明确要求使用"bash脚本"，但它也提到了mac os x类似于BSD的非GNUreadlink。所以这里有一个合理的可移植性的尝试(我用bash检查了它作为'sh'和dash)，解析任意数量的符号链接；它也应该在路径中使用空格，尽管我不确定是否存在空格(实用程序本身的基名)，那么也许，嗯，避免这样做？

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#!/bin/sh
realpath() {
OURPWD=$PWD
cd"$(dirname"$1")"
LINK=$(readlink"$(basename"$1")")
while ["$LINK" ]; do
cd"$(dirname"$LINK")"
LINK=$(readlink"$(basename"$1")")
done
REALPATH="$PWD/$(basename"$1")"
cd"$OURPWD"
echo"$REALPATH"
}
realpath"$@"

希望这对某人有用。

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python解决方案的一个更友好的命令行变体：

1	python -c"import os; print(os.path.realpath('$1'))"

因为有一条真正的道路，正如其他人所指出的：

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// realpath.c
#include <stdio.h>
#include <stdlib.h>

int main (int argc, char* argv[])
{
if (argc > 1) {
for (int argIter = 1; argIter < argc; ++argIter) {
char *resolved_path_buffer = NULL;
char *result = realpath(argv[argIter], resolved_path_buffer);

puts(result);

if (result != NULL) {
free(result);
}
}
}

return 0;
}

Makefile：

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#Makefile
OBJ = realpath.o

%.o: %.c
$(CC) -c -o $@ $< $(CFLAGS)

realpath: $(OBJ)
gcc -o $@ $^ $(CFLAGS)

然后用make编译，并与以下对象建立软链接：ln -s $(pwd)/realpath /usr/local/bin/realpath

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使用python获取：

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#!/usr/bin/env python
import os
import sys

print(os.path.realpath(sys.argv[1]))

我正在寻找一个可用于系统配置脚本的解决方案，即在安装自制之前运行。由于缺乏适当的解决方案，我只需将任务卸载到跨平台语言，例如Perl:

1	script_abspath=$(perl -e 'use Cwd"abs_path"; print abs_path(@ARGV[0])' --"$0")

通常我们真正想要的是包含目录：

1	here=$(perl -e 'use File::Basename; use Cwd"abs_path"; print dirname(abs_path(@ARGV[0]));' --"$0")

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正如你在上面看到的，大约6个月前我拍了一张照片。我完全忘了它，直到我发现自己又需要类似的东西。我是完全震惊地看到它是多么的初级；我一直在教书我自己已经花了大约一年的时间集中编写代码了，但我经常觉得也许在最坏的时候我什么都没学到。

我会删除上面的"解决方案"，但我真的希望它是在过去的几个月里我真正学到了多少。

但我离题了。我昨天晚上坐下来，把一切都解决了。解释这些评论应该足够了。如果你想追踪副本，我会继续为了继续工作，你可以遵循这个要点。这可能是你需要的。

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#!/bin/sh # dash bash ksh # !zsh (issues). G. Nixon, 12/2013. Public domain.

## 'linkread' or 'fullpath' or (you choose) is a little tool to recursively
## dereference symbolic links (ala 'readlink') until the originating file
## is found. This is effectively the same function provided in stdlib.h as
## 'realpath' and on the command line in GNU 'readlink -f'.

## Neither of these tools, however, are particularly accessible on the many
## systems that do not have the GNU implementation of readlink, nor ship
## with a system compiler (not to mention the requisite knowledge of C).

## This script is written with portability and (to the extent possible, speed)
## in mind, hence the use of printf for echo and case statements where they
## can be substituded for test, though I've had to scale back a bit on that.

## It is (to the best of my knowledge) written in standard POSIX shell, and
## has been tested with bash-as-bin-sh, dash, and ksh93. zsh seems to have
## issues with it, though I'm not sure why; so probably best to avoid for now.

## Particularly useful (in fact, the reason I wrote this) is the fact that
## it can be used within a shell script to find the path of the script itself.
## (I am sure the shell knows this already; but most likely for the sake of
## security it is not made readily available. The implementation of"$0"
## specificies that the $0 must be the location of **last** symbolic link in
## a chain, or wherever it resides in the path.) This can be used for some
## ...interesting things, like self-duplicating and self-modifiying scripts.

## Currently supported are three errors: whether the file specified exists
## (ala ENOENT), whether its target exists/is accessible; and the special
## case of when a sybolic link references itself"foo -> foo": a common error
## for beginners, since 'ln' does not produce an error if the order of link
## and target are reversed on the command line. (See POSIX signal ELOOP.)

## It would probably be rather simple to write to use this as a basis for
## a pure shell implementation of the 'symlinks' util included with Linux.

## As an aside, the amount of code below **completely** belies the amount
## effort it took to get this right -- but I guess that's coding for you.

##===-------------------------------------------------------------------===##

for argv; do :; done # Last parameter on command line, for options parsing.

## Error messages. Use functions so that we can sub in when the error occurs.

recurses(){ printf"Self-referential:
\t$argv ->
\t$argv
" ;}
dangling(){ printf"Broken symlink:
\t$argv ->
\t"$(readlink"$argv")"
" ;}
errnoent(){ printf"No such file:"$@"
" ;} # Borrow a horrible signal name.

# Probably best not to install as 'pathfull', if you can avoid it.

pathfull(){ cd"$(dirname"$@")"; link="$(readlink"$(basename"$@")")"

## 'test and 'ls' report different status for bad symlinks, so we use this.

if [ ! -e"$@" ]; then if $(ls -d"$@" 2>/dev/null) 2>/dev/null; then
errnoent 1>&2; exit 1; elif [ ! -e"$@" -a"$link" ="$@" ]; then
recurses 1>&2; exit 1; elif [ ! -e"$@" ] && [ ! -z"$link" ]; then
dangling 1>&2; exit 1; fi
fi

## Not a link, but there might be one in the path, so 'cd' and 'pwd'.

if [ -z"$link" ]; then if ["$(dirname"$@" | cut -c1)" = '/' ]; then
printf"$@
"; exit 0; else printf"$(pwd)/$(basename"$@")
"; fi; exit 0
fi

## Walk the symlinks back to the origin. Calls itself recursivly as needed.

while ["$link" ]; do
cd"$(dirname"$link")"; newlink="$(readlink"$(basename"$link")")"
case"$newlink" in
"$link") dangling 1>&2 && exit 1 ;;
'') printf"$(pwd)/$(basename"$link")
"; exit 0 ;;
*) link="$newlink" && pathfull"$link" ;;
esac
done
printf"$(pwd)/$(basename"$newlink")
"
}

## Demo. Install somewhere deep in the filesystem, then symlink somewhere
## else, symlink again (maybe with a different name) elsewhere, and link
## back into the directory you started in (or something.) The absolute path
## of the script will always be reported in the usage, along with"$0".

if [ -z"$argv" ]; then scriptname="$(pathfull"$0")"

# Yay ANSI l33t codes! Fancy.
printf"
\033[3mfrom/as: \033[4m$0\033[0m

\033[1mUSAGE:\033[0m "
printf"\033[4m$scriptname\033[24m [ link | file | dir ]

"
printf"Recursive readlink for the authoritative file, symlink after"
printf"symlink.

\033[4m$scriptname\033[24m

"
printf" From within an invocation of a script, locate the script's"
printf"own file
(no matter where it has been linked or"
printf"from where it is being called).

"

else pathfull"$@"
fi

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Mac OS X的realpath

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realpath() {
path=`eval echo"$1"`
folder=$(dirname"$path")
echo $(cd"$folder"; pwd)/$(basename"$path");
}

具有相关路径的示例：

1	realpath"../scripts/test.sh"

主文件夹示例

1	realpath"~/Test/../Test/scripts/test.sh"

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基于与评论者的沟通，我同意这是非常困难的，没有繁琐的方式来实现一个真正的路径行为完全相同的Ubuntu。

但下面的版本，可以处理角箱的最佳答案，不能满足我对MacBook的日常需求。将此代码放入~/.bashrc并记住：

arg只能是1个文件或目录，没有通配符
目录或文件名中没有空格
至少存在文件或目录的父目录
请随意使用。…/东西，这些是安全的

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# 1. if is a dir, try cd and pwd
# 2. if is a file, try cd its parent and concat dir+file
realpath() {
["$1" ="" ] && return 1

dir=`dirname"$1"`
file=`basename"$1"`

last=`pwd`

[ -d"$dir" ] && cd $dir || return 1
if [ -d"$file" ];
then
# case 1
cd $file && pwd || return 1
else
# case 2
echo `pwd`/$file | sed 's/\/\//\//g'
fi

cd $last
}

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