如何在Bash中规范化文件路径?

我想转换/foo/bar/../ foo

是否有bash命令可以做到这一点?

编辑:在我的实际案例中，目录确实存在。

当前回答

试试我们新的Bash库产品realpath-lib吧，我们已经把它放在GitHub上了，可以免费、不受阻碍地使用。它有完整的文档，是一个很好的学习工具。

它可以解析本地、相对和绝对路径，除了Bash 4+，它没有任何依赖关系;所以它应该适用于任何地方。它是免费的，干净的，简单的和有教育意义的。

你可以:

get_realpath <absolute|relative|symlink|local file path>

这个函数是库的核心:

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

}

它还包含get_dirname, get_filename, get_ stemname和validate_path函数。在不同平台上尝试它，并帮助改进它。

2013-10-02 15:52:19

其他回答

基于loveborg出色的python代码片段，我这样写:

#!/bin/sh

# Version of readlink that follows links to the end; good for Mac OS X

for file in "$@"; do
  while [ -h "$file" ]; do
    l=`readlink $file`
    case "$l" in
      /*) file="$l";;
      *) file=`dirname "$file"`/"$l"
    esac
  done
  #echo $file
  python -c "import os,sys; print os.path.abspath(sys.argv[1])" "$file"
done

2016-03-16 19:24:16

我需要一个同时满足这三点的解决方案:

在普通mac上工作。realpath和readlink -f是插件解决符号链接有错误处理

没有一个人的答案同时包含了第一条和第二条。我加了第三条是为了让其他人不用再剃牦牛了。

#!/bin/bash

P="${1?Specify a file path}"

[ -e "$P" ] || { echo "File does not exist: $P"; exit 1; }

while [ -h "$P" ] ; do
    ls="$(ls -ld "$P")"
    link="$(expr "$ls" : '.*-> \(.*\)$')"
    expr "$link" : '/.*' > /dev/null &&
        P="$link" ||
        P="$(dirname "$P")/$link"
done
echo "$(cd "$(dirname "$P")"; pwd)/$(basename "$P")"

下面是一个简短的测试用例，在路径中有一些扭曲的空格，以充分练习引用

mkdir -p "/tmp/test/ first path "
mkdir -p "/tmp/test/ second path "
echo "hello" > "/tmp/test/ first path / red .txt "
ln -s "/tmp/test/ first path / red .txt " "/tmp/test/ second path / green .txt "

cd  "/tmp/test/ second path "
fullpath " green .txt "
cat " green .txt "

2018-05-16 01:53:30

如果您想要从路径中删除部分文件名，“dirname”和“basename”是您的朋友，“realpath”也很方便。

dirname /foo/bar/baz 
# /foo/bar 
basename /foo/bar/baz
# baz
dirname $( dirname  /foo/bar/baz  ) 
# /foo 
realpath ../foo
# ../foo: No such file or directory
realpath /tmp/../tmp/../tmp
# /tmp

realpath替代品

如果您的shell不支持realpath，您可以尝试

readlink -f /path/here/..

Also

readlink -m /path/there/../../

工作原理与

realpath -s /path/here/../../

在这种情况下，路径不需要存在就可以被规范化。

2008-11-12 17:20:40

如果你只想规范化一个路径，不管是否存在，不涉及文件系统，不解析任何链接，也不使用外部utils，这里有一个从Python的posixpath.normpath转换而来的纯Bash函数。

#!/usr/bin/env bash

# Normalize path, eliminating double slashes, etc.
# Usage: new_path="$(normpath "${old_path}")"
# Translated from Python's posixpath.normpath:
# https://github.com/python/cpython/blob/master/Lib/posixpath.py#L337
normpath() {
  local IFS=/ initial_slashes='' comp comps=()
  if [[ $1 == /* ]]; then
    initial_slashes='/'
    [[ $1 == //* && $1 != ///* ]] && initial_slashes='//'
  fi
  for comp in $1; do
    [[ -z ${comp} || ${comp} == '.' ]] && continue
    if [[ ${comp} != '..' || (-z ${initial_slashes} && ${#comps[@]} -eq 0) || (\
      ${#comps[@]} -gt 0 && ${comps[-1]} == '..') ]]; then
      comps+=("${comp}")
    elif ((${#comps[@]})); then
      unset 'comps[-1]'
    fi
  done
  comp="${initial_slashes}${comps[*]}"
  printf '%s\n' "${comp:-.}"
}

例子:

new_path="$(normpath '/foo/bar/..')"
echo "${new_path}"
# /foo

normpath "relative/path/with trailing slashs////"
# relative/path/with trailing slashs

normpath "////a/../lot/././/mess////./here/./../"
# /lot/mess

normpath ""
# .
# (empty path resolved to dot)

Personally, I cannot understand why Shell, a language often used for manipulating files, doesn't offer basic functions to deal with paths. In python, we have nice libraries like os.path or pathlib, which offers a whole bunch of tools to extract filename, extension, basename, path segments, split or join paths, to get absolute or normalized paths, to determine relations between paths, to do everything without much brain. And they take care of edge cases, and they're reliable. In Shell, to do any of these, either we call external executables, or we have to reinvent wheels with these extremely rudimentary and arcane syntaxes...

2021-03-04 05:08:17