我如何在Mac上获得GNU readlink-f的行为?[关闭]

MacPorts和Homebrew提供了 greadlink

brew install coreutils

greadlink -f file.txt

readlink -f 做两件事:

1. 它沿着一系列符号链接迭代,直到找到一个实际的文件。

如果你愿意,你可以构建一个使用vanilla readlink行为的shell脚本来实现同样的功能。这里有一个例子。显然,您可以将其插入到您自己的脚本中您想调用的位置

#!/bin/sh

TARGET_FILE=$1

cd `dirname $TARGET_FILE`
TARGET_FILE=`basename $TARGET_FILE`

# Iterate down a (possible) chain of symlinks
while [ -L "$TARGET_FILE" ]
do
    TARGET_FILE=`readlink $TARGET_FILE`
    cd `dirname $TARGET_FILE`
    TARGET_FILE=`basename $TARGET_FILE`
done

# Compute the canonicalized name by finding the physical path 
# for the directory we're in and appending the target file.
PHYS_DIR=`pwd -P`
RESULT=$PHYS_DIR/$TARGET_FILE
echo $RESULT

请注意,这不包括任何错误处理。特别重要的是,它不会检测符号链接循环。一个简单的方法是计算你在循环中循环的次数,如果你遇到一个难以置信的大数字,比如1000,就会失败。

pwd -P $PWD .

./script_name filename ,没有 -f $1 $2 -f filename

realpath(3) os.path.realpath

$ pwd
/tmp/foo
$ ls -l
total 16
-rw-r--r--  1 miles    wheel  0 Jul 11 21:08 a
lrwxr-xr-x  1 miles    wheel  1 Jul 11 20:49 b -> a
lrwxr-xr-x  1 miles    wheel  1 Jul 11 20:49 c -> b
$ python -c 'import os,sys;print(os.path.realpath(sys.argv[1]))' c
/private/tmp/foo/a

#!/usr/bin/python

import ctypes, sys

libc = ctypes.CDLL('libc.dylib')
libc.realpath.restype = ctypes.c_char_p
libc.__error.restype = ctypes.POINTER(ctypes.c_int)
libc.strerror.restype = ctypes.c_char_p

def realpath(path):
    buffer = ctypes.create_string_buffer(1024) # PATH_MAX
    if libc.realpath(path, buffer):
        return buffer.value
    else:
        errno = libc.__error().contents.value
        raise OSError(errno, "%s: %s" % (libc.strerror(errno), buffer.value))

if __name__ == '__main__':
    print realpath(sys.argv[1])

perl -MCwd -e 'print Cwd::abs_path shift' ~/non-absolute/file

将取消引用符号链接。

readlinkf(){ perl -MCwd -e 'print Cwd::abs_path shift' "$1";}
ABSPATH="$(readlinkf ./non-absolute/file)"

你可能两者都需要 .

看 my project on Github

readlink -f

realpath() {
    canonicalize_path "$(resolve_symlinks "$1")"
}

首先,符号链接解析器实现:

resolve_symlinks() {
    local dir_context path
    path=$(readlink -- "$1")
    if [ $? -eq 0 ]; then
        dir_context=$(dirname -- "$1")
        resolve_symlinks "$(_prepend_path_if_relative "$dir_context" "$path")"
    else
        printf '%s\n' "$1"
    fi
}

_prepend_path_if_relative() {
    case "$2" in
        /* ) printf '%s\n' "$2" ;;
         * ) printf '%s\n' "$1/$2" ;;
    esac 
}

the full implementation .

canonicalize_path() {
    if [ -d "$1" ]; then
        _canonicalize_dir_path "$1"
    else
        _canonicalize_file_path "$1"
    fi
}   

_canonicalize_dir_path() {
    (cd "$1" 2>/dev/null && pwd -P) 
}           
        
_canonicalize_file_path() {
    local dir file
    dir=$(dirname -- "$1")
    file=$(basename -- "$1")
    (cd "$dir" 2>/dev/null && printf '%s/%s\n' "$(pwd -P)" "$file")
}

1. 安装自制程序

#!/usr/bin/env python
import os, sys
print(os.path.realpath(sys.argv[1]))

function readlink() {
  DIR="${1%/*}"
  (cd "$DIR" && echo "$(pwd -P)")
}

$ brew install coreutils
$ ln -s /usr/local/bin/greadlink /usr/local/bin/readlink
$ which readlink
/usr/local/bin/readlink
/usr/bin/readlink

请遵循以下说明 https://brew.sh/

brew install coreutils

3a。创建别名(每个用户)

您可以将别名放在~/.bashrc、~/.bash_profile或任何您习惯保留bash别名的地方。我个人把我的放在~/.bashrc中

alias readlink=greadlink

ln -s /usr/local/bin/greadlink /usr/local/bin/readlink

这将在/usr/local/bin中创建一个符号链接,同时保持原始的readlink二进制文件不变。它之所以有效,是因为搜索readlink将返回2个结果。但是/usr/local/bin中的第二个将优先。

which readlink

unlink /usr/local/bin/readlink

其他工具

brew 安装GNU/Linux核心实用程序的软件包,这些实用程序与Mac OSX实现相对应,以便您可以使用它们

coreutils 酿造

g readlink greadlink

为了使 读取链接 ( 油性油墨

FreeBSD 和 OSX stat

%  cd  /service
%  ls -tal 
drwxr-xr-x 22 root wheel 27 Aug 25 10:41 ..
drwx------  3 root wheel  8 Jun 30 13:59 .s6-svscan
drwxr-xr-x  3 root wheel  5 Jun 30 13:34 .
lrwxr-xr-x  1 root wheel 30 Dec 13 2013 clockspeed-adjust -> /var/service/clockspeed-adjust
lrwxr-xr-x  1 root wheel 29 Dec 13 2013 clockspeed-speed -> /var/service/clockspeed-speed
% stat -f%R  clockspeed-adjust
/var/service/clockspeed-adjust
% stat -f%Y  clockspeed-adjust
/var/service/clockspeed-adjust

-f%R 格式选项。在这种情况下 -stat -f%Y -f%Y -f%R 显示了与文件对应的绝对路径名。

perl

perl -MCwd=abs_path -le 'print abs_path readlink(shift);' linkedfile.txt

# pkg install coreutils

$ brew install coreutils

如果由于某种原因您没有realpath(1)命令或readlink(1),这可能会被别名化。

which realpath || alias realpath='real_path'

real_path () {
  OIFS=$IFS
  IFS='/'
  for I in $1
  do
    # Resolve relative path punctuation.
    if [ "$I" = "." ] || [ -z "$I" ]
      then continue
    elif [ "$I" = ".." ]
      then FOO="${FOO%%/${FOO##*/}}"
           continue
      else FOO="${FOO}/${I}"
    fi

    ## Resolve symbolic links
    if [ -h "$FOO" ]
    then
    IFS=$OIFS
    set `ls -l "$FOO"`
    while shift ;
    do
      if [ "$1" = "->" ]
        then FOO=$2
             shift $#
             break
      fi
    done
    IFS='/'
    fi
  done
  IFS=$OIFS
  echo "$FOO"
}

## http://www.opengroup.org/onlinepubs/000095399/functions/dirname.html
# the dir name excludes the least portion behind the last slash.
dir_name () {
  echo "${1%/*}"
}

## http://www.opengroup.org/onlinepubs/000095399/functions/basename.html
# the base name excludes the greatest portion in front of the last slash.
base_name () {
  echo "${1##*/}"
}

http://sites.google.com/site/jdisnard/realpath

编辑:

github.com 或 bitbucket.org .

另一个非常紧凑和高效的解决方案不依赖于Bash之外的任何东西:

function get_realpath() {

    [[ ! -f "$1" ]] && return 1 # failure : file does not exist.
    [[ -n "$no_symlinks" ]] && local pwdp='pwd -P' || local pwdp='pwd' # do symlinks.
    echo "$( cd "$( echo "${1%/*}" )" 2>/dev/null; $pwdp )"/"${1##*/}" # echo result.
    return 0 # success

}

这也包括环境设置 no_symlinks 它提供了解析物理系统符号链接的能力。只要 无符号链接 no_symlinks='on'

readlink_f() {
  local target="$1"
  [ -f "$target" ] || return 1 #no nofile

  while [ -L "$target" ]; do
    target="$(readlink "$target")" 
  done
  echo "$(cd "$(dirname "$target")"; pwd -P)/$target"
}

sed

##
# If you're running macOS, use homebrew to install greadlink/gsed first:
#   brew install coreutils
#
# Example use:
#   # Gets the directory of the currently running script
#   dotfilesDir=$(dirname "$(globalReadlink -fm "$0")")
#   alias al='pico ${dotfilesDir}/aliases.local'
##

function globalReadlink () {
  # Use greadlink if on macOS; otherwise use normal readlink
  if [[ $OSTYPE == darwin* ]]; then
    greadlink "$@"
  else
    readlink "$@"
  fi
}

function globalSed () {
  # Use gsed if on macOS; otherwise use normal sed
  if [[ $OSTYPE == darwin* ]]; then
    gsed "$@"
  else
    sed "$@"
  fi
}

homebrew coreutils 依赖关系:

if [[ "$OSTYPE" == "darwin"* ]]; then
  # Install brew if needed
  if [ -z "$(which brew)" ]; then 
    /usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"; 
  fi
  # Check for coreutils
  if [ -z "$(brew ls coreutils)" ]; then
    brew install coreutils
  fi
fi

readlink -f

https://github.com/ko1nksm/readlinkf

readlink realpath (参见 test results 许可证为CC0,因此您可以将其用于任何项目。

本规范在 bats-core

# POSIX compliant version
readlinkf_posix() {
  [ "${1:-}" ] || return 1
  max_symlinks=40
  CDPATH='' # to avoid changing to an unexpected directory

  target=$1
  [ -e "${target%/}" ] || target=${1%"${1##*[!/]}"} # trim trailing slashes
  [ -d "${target:-/}" ] && target="$target/"

  cd -P . 2>/dev/null || return 1
  while [ "$max_symlinks" -ge 0 ] && max_symlinks=$((max_symlinks - 1)); do
    if [ ! "$target" = "${target%/*}" ]; then
      case $target in
        /*) cd -P "${target%/*}/" 2>/dev/null || break ;;
        *) cd -P "./${target%/*}" 2>/dev/null || break ;;
      esac
      target=${target##*/}
    fi

    if [ ! -L "$target" ]; then
      target="${PWD%/}${target:+/}${target}"
      printf '%s\n' "${target:-/}"
      return 0
    fi

    # `ls -dl` format: "%s %u %s %s %u %s %s -> %s\n",
    #   <file mode>, <number of links>, <owner name>, <group name>,
    #   <size>, <date and time>, <pathname of link>, <contents of link>
    # https://pubs.opengroup.org/onlinepubs/9699919799/utilities/ls.html
    link=$(ls -dl -- "$target" 2>/dev/null) || break
    target=${link#*" $target -> "}
  done
  return 1
}

echo$(cd$(目录名file1);pwd-P)

回声 和 。它也相当安全,因为所有内容都会在每个阶段进行测试,并返回错误条件。

如果你不想遵循符号链接,那么放 光盘

function get_realpath() {

if [[ -f "$1" ]]
then
    # file *must* exist
    if cd "$(echo "${1%/*}")" &>/dev/null
    then
        # file *may* not be local
        # exception is ./file.ext
        # try 'cd .; cd -;' *works!*
        local tmppwd="$PWD"
        cd - &>/dev/null
    else
        # file *must* be local
        local tmppwd="$PWD"
    fi
else
    # file *cannot* exist
    return 1 # failure
fi

# reassemble realpath
echo "$tmppwd"/"${1##*/}"
return 0 # success

}

realpath-lib (完全披露-这是我们的产品,但我们免费向社区提供,没有任何限制)。它也可以作为一种教学工具——它有很好的记录。

我们已经尽力应用所谓的“现代Bash”实践,但Bash是一个很大的主题,我相信总会有改进的空间。它需要Bash 4+,但如果旧版本仍然存在,可以使其与旧版本一起工作。

我写的 a realpath utility for OS X readlink -f .

(jalcazar@mac tmp)$ ls -l a
lrwxrwxrwx 1 jalcazar jalcazar 11  8月 25 19:29 a -> /etc/passwd

(jalcazar@mac tmp)$ realpath a
/etc/passwd

sudo port selfupdate && sudo port install realpath .

真正的平台依赖者也是这个R-onliner

readlink(){ RScript -e "cat(normalizePath(commandArgs(T)[1]))" "$1";}

readlink -f <path>

#!/usr/bin/env bash -e

declare script=$(basename "$0")
declare dirname=$(dirname "$0")
declare scriptDir
if [[ $(uname) == 'Linux' ]];then
    # use readlink -f
    scriptDir=$(readlink -f "$dirname")
else
    # can't use readlink -f, do a pwd -P in the script directory and then switch back
    if [[ "$dirname" = '.' ]];then
        # don't change directory, we are already inside
        scriptDir=$(pwd -P)
    else
        # switch to the directory and then switch back
        pwd=$(pwd)
        cd "$dirname"
        scriptDir=$(pwd -P)
        cd "$pwd"
    fi
fi

readlink -f . $scriptDir 和 $script

pwd -P

How do I copy symbolic links in Perl? ).这适用于大多数平台,包括OS X:

perl -e "print readlink '/path/to/link'"

$ mkdir -p a/b/c
$ ln -s a/b/c x
$ perl -e "print readlink 'x'"
a/b/c

#!/bin/sh
! (($#)) && echo -e "ERROR: readlink <link to analyze>" 1>&2 && exit 99

link="$1"
while [ -L "$link" ]; do
  lastLink="$link"
  link=$(/bin/ls -ldq "$link")
  link="${link##* -> }"
  link=$(realpath "$link")
  [ "$link" == "$lastlink" ] && echo -e "ERROR: link loop detected on $link" 1>&2 && break
done

echo "$link"

stat -f %N $your_path