将相对路径转换为绝对路径?

从 this source

#!/bin/bash

# Assume parameter passed in is a relative path to a directory.
# For brevity, we won't do argument type or length checking.

ABS_PATH=`cd "$1"; pwd` # double quotes for paths that contain spaces etc...
echo "Absolute path: $ABS_PATH"

您还可以使用Perl一行程序,例如 Cwd::abs_path

我在unix中遇到的最可靠的方法是 readlink -f :

$ readlink -f /x/y/../../a/b/z/../c/d
/a/b/c/d

1. 这还具有解析所有符号链接的副作用。这可能是可取的,也可能不是可取的,但通常是可取的。
2. readlink readlink -m 相反。不幸的是,此选项在~2005年之前发布的readlink版本中不存在。

看看“realpath”。

$ realpath

usage: realpath [-q] path [...]

$ realpath ../../../../../

/data/home

bash

# Directory
relative_dir="folder/subfolder/"
absolute_dir="$( cd "$relative_dir" && pwd )"

# File
relative_file="folder/subfolder/file"
absolute_file="$( cd "${relative_file%/*}" && pwd )"/"${relative_file##*/}"

• ${relative_file%/*} 结果与 dirname "$relative_file"
• ${relative_file##*/} 结果与 basename "$relative_file"

:不解析符号链接(即不规范路径)=>如果使用符号链接,则可能无法区分所有重复项。

使用 realpath

realpath 完成任务。另一种选择是 readlink -e (或 readlink -f ). 然而 再分配 默认情况下不经常安装。如果你不能确定 再分配 readlink 现在,您可以使用perl替换它(见下文)。

使用 perl

Steven Kramer 再分配 在您的系统中不可用:

$ alias realpath="perl -MCwd -e 'print Cwd::realpath(\$ARGV[0]),qq<\n>'"
$ realpath path/folder/file
/home/user/absolute/path/folder/file

或者如果您喜欢直接使用perl:

$ perl -MCwd -e 'print Cwd::realpath($ARGV[0]),qq<\n>' path/folder/file
/home/user/absolute/path/folder/file

这一行perl命令使用 Cwd::realpath Perl5 > Core modules > Cwd .

• abs_path() 使用与 getcwd() . 和 .. )决定返回规范路径名,就像 .

  use Cwd 'abs_path';
  my $abs_path = abs_path($file);
  

• realpath() 是 绝对路径()

  use Cwd 'realpath';
  my $abs_path = realpath($file);
  

• fast_abs_path() 是一个更危险,但可能更快的版本 绝对路径()

  use Cwd 'fast_abs_path';
  my $abs_path = fast_abs_path($file);
  

Cwd 为了避免 “未定义的子例程” 由指出的错误 arielf use Cwd 行:

use Cwd qw(abs_path realpath fast_abs_path);

多年来,我遇到过很多次这种情况,这次我需要一个纯bash的可移植版本,可以在OSX和linux上使用,所以我继续写了一篇:

活生生的版本住在这里:

https://github.com/keen99/shell-functions/tree/master/resolve_path

对于普通的bourne shell(sh)来说,这可能并不难,但我没有尝试……我太喜欢$FUNCNAME了。:)

#!/bin/bash

resolve_path() {
    #I'm bash only, please!
    # usage:  resolve_path <a file or directory> 
    # follows symlinks and relative paths, returns a full real path
    #
    local owd="$PWD"
    #echo "$FUNCNAME for $1" >&2
    local opath="$1"
    local npath=""
    local obase=$(basename "$opath")
    local odir=$(dirname "$opath")
    if [[ -L "$opath" ]]
    then
    #it's a link.
    #file or directory, we want to cd into it's dir
        cd $odir
    #then extract where the link points.
        npath=$(readlink "$obase")
        #have to -L BEFORE we -f, because -f includes -L :(
        if [[ -L $npath ]]
         then
        #the link points to another symlink, so go follow that.
            resolve_path "$npath"
            #and finish out early, we're done.
            return $?
            #done
        elif [[ -f $npath ]]
        #the link points to a file.
         then
            #get the dir for the new file
            nbase=$(basename $npath)
            npath=$(dirname $npath)
            cd "$npath"
            ndir=$(pwd -P)
            retval=0
            #done
        elif [[ -d $npath ]]
         then
        #the link points to a directory.
            cd "$npath"
            ndir=$(pwd -P)
            retval=0
            #done
        else
            echo "$FUNCNAME: ERROR: unknown condition inside link!!" >&2
            echo "opath [[ $opath ]]" >&2
            echo "npath [[ $npath ]]" >&2
            return 1
        fi
    else
        if ! [[ -e "$opath" ]]
         then
            echo "$FUNCNAME: $opath: No such file or directory" >&2
            return 1
            #and break early
        elif [[ -d "$opath" ]]
         then 
            cd "$opath"
            ndir=$(pwd -P)
            retval=0
            #done
        elif [[ -f "$opath" ]]
         then
            cd $odir
            ndir=$(pwd -P)
            nbase=$(basename "$opath")
            retval=0
            #done
        else
            echo "$FUNCNAME: ERROR: unknown condition outside link!!" >&2
            echo "opath [[ $opath ]]" >&2
            return 1
        fi
    fi
    #now assemble our output
    echo -n "$ndir"
    if [[ "x${nbase:=}" != "x" ]]
     then
        echo "/$nbase"
    else 
        echo
    fi
    #now return to where we were
    cd "$owd"
    return $retval
}

下面是一个典型的例子,感谢brew:

%% ls -l `which mvn`
lrwxr-xr-x  1 draistrick  502  29 Dec 17 10:50 /usr/local/bin/mvn@ -> ../Cellar/maven/3.2.3/bin/mvn

%% cat test.sh
#!/bin/bash
. resolve_path.inc
echo
echo "relative symlinked path:"
which mvn
echo
echo "and the real path:"
resolve_path `which mvn`


%% test.sh

relative symlinked path:
/usr/local/bin/mvn

and the real path:
/usr/local/Cellar/maven/3.2.3/libexec/bin/mvn

这可能有助于:

$path = "~user/dir/../file" 
$resolvedPath = glob($path); #   (To resolve paths with '~')
# Since glob does not resolve relative path, we use abs_path 
$absPath      = abs_path($path);