在Linux上,readlink实用程序接受附加链接后面的选项-f。这似乎不适用于Mac和基于BSD的系统。等价的是什么?
下面是一些调试信息:
$ which readlink; readlink -f
/usr/bin/readlink
readlink: illegal option -f
usage: readlink [-n] [file ...]
在Linux上,readlink实用程序接受附加链接后面的选项-f。这似乎不适用于Mac和基于BSD的系统。等价的是什么?
下面是一些调试信息:
$ which readlink; readlink -f
/usr/bin/readlink
readlink: illegal option -f
usage: readlink [-n] [file ...]
当前回答
来自@Keith Smith的回答给出了一个无限循环。
这是我的答案,我只在SunOS上使用(SunOS错过了很多POSIX和GNU命令)。
这是一个脚本文件,你必须把它放在你的$PATH目录之一:
#!/bin/sh
! (($#)) && 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"
其他回答
由于使用非bsd Linux和macOS的人都使用我的工作,所以我选择在构建脚本中使用这些别名(包括sed,因为它有类似的问题):
##
# 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 "$@"
fi
}
可选检查,您可以添加自动安装homebrew + coreutils依赖项:
if [[ "$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
我想要真正做到“全球化”,它需要检查其他国家……但这可能接近80/20的标记。
Echo $(cd $(dirname file1);pwd - p)
一种适合我的偷懒方式,
$ brew install coreutils
$ ln -s /usr/local/bin/greadlink /usr/local/bin/readlink
$ which readlink
/usr/local/bin/readlink
/usr/bin/readlink
开始更新
This is such a frequent problem that we have put together a Bash 4 library for free use (MIT License) called realpath-lib. This is designed to emulate readlink -f by default and includes two test suites to verify (1) that it works for a given unix system and (2) against readlink -f if installed (but this is not required). Additionally, it can be used to investigate, identify and unwind deep, broken symlinks and circular references, so it can be a useful tool for diagnosing deeply-nested physical or symbolic directory and file problems. It can be found at github.com or bitbucket.org.
最后更新
另一个非常紧凑和高效的解决方案,它只依赖于Bash:
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
}
这还包括一个环境设置no_symlinks,它提供了将符号链接解析到物理系统的能力。只要no_symlinks被设置为某个值,即no_symlinks='on',那么symlinks将被解析为物理系统。否则将应用它们(默认设置)。
这应该可以在任何提供Bash的系统上工作,并将返回一个与Bash兼容的退出代码用于测试。
真正的平台独立也是r -online
readlink(){ RScript -e "cat(normalizePath(commandArgs(T)[1]))" "$1";}
要实际模拟readlink -f <path>,需要使用$2而不是$1。