我相信我得到了这个一个,我迟到了派对,但我认为有些人会欣赏它在这里,如果他们通过这个条纹。

#!/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:\n\t$argv ->\n\t$argv\n" ;}
dangling(){ printf "Broken symlink:\n\t$argv ->\n\t"$(readlink "$argv")"\n" ;}
errnoent(){ printf "No such file: "$@"\n" ;} # 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 "$@" | cut -c1)" = '/' ]; then
   printf "$@\n"; exit 0; else printf "$(pwd)/$(basename "$@")\n"; 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 "$link")\n"; exit 0                 ;;
          *) link="$newlink" && pathfull "$link"                           ;;
   esac
 done
 printf "$(pwd)/$(basename "$newlink")\n"
}

## 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 "\n\033[3mfrom/as: \033[4m$0\033[0m\n\n\033[1mUSAGE:\033[0m   "
 printf "\033[4m$scriptname\033[24m [ link | file | dir ]\n\n         "
 printf "Recursive readlink for the authoritative file, symlink after "
 printf "symlink.\n\n\n         \033[4m$scriptname\033[24m\n\n        "
 printf " From within an invocation of a script, locate the script's "
 printf "own file\n         (no matter where it has been linked or "
 printf "from where it is being called).\n\n"

else pathfull "$@"
fi

function getScriptAbsoluteDir { # fold>>
    # @description used to get the script path
    # @param $1 the script $0 parameter
    local script_invoke_path="$1"
    local cwd=`pwd`

    # absolute path ? if so, the first character is a /
    if test "x${script_invoke_path:0:1}" = 'x/'
    then
        RESULT=`dirname "$script_invoke_path"`
    else
        RESULT=`dirname "$cwd/$script_invoke_path"`
    fi
} # <<fold

我想评论上面的答案(我如何从脚本本身中获取Bash脚本的源目录?),但没有足够的声誉来做到这一点。

我在两年前在苹果的文档网站上找到了一个解决方案: https://developer.apple.com/library/archive/documentation/OpenSource/Conceptual/ShellScripting/AdvancedTechniques/AdvancedTechniques.html。

#!/bin/sh

# Get an absolute path for the poem.txt file.
POEM="$PWD/../poem.txt"

# Get an absolute path for the script file.
SCRIPT="$(which $0)"
if [ "x$(echo $SCRIPT | grep '^\/')" = "x" ] ; then
    SCRIPT="$PWD/$SCRIPT"
fi

正如代码所表明的那样,一旦您获得脚本的绝对路径,则您可以使用命令命名以获得目录的路径。

#!/bin/sh
PRG="$0"

# need this for relative symlinks
while [ -h "$PRG" ] ; do
   PRG=`readlink "$PRG"`
done

scriptdir=`dirname "$PRG"`

关键部分是,我正在减少问题的范围:我禁止通过路径间接执行脚本(如 /bin/sh [脚本路径与路径组件有关])。

这可以被检测到,因为0美元将是一个相对的路径,不解决与当前文件夹有关的任何文件。我相信使用#!机制的直接执行总是导致绝对0美元,包括当脚本在路径上找到时。

我也要求在象征性链接链接链接的任何字符和字符只包含一个合理的字符子,特别是不是 \n, >, * 或?. 这对于字符逻辑来说是必要的。

#!/bin/sh
(
    path="${0}"
    while test -n "${path}"; do
        # Make sure we have at least one slash and no leading dash.
        expr "${path}" : / > /dev/null || path="./${path}"
        # Filter out bad characters in the path name.
        expr "${path}" : ".*[*?<>\\]" > /dev/null && exit 1
        # Catch embedded new-lines and non-existing (or path-relative) files.
        # $0 should always be absolute when scripts are invoked through "#!".
        test "`ls -l -d "${path}" 2> /dev/null | wc -l`" -eq 1 || exit 1
        # Change to the folder containing the file to resolve relative links.
        folder=`expr "${path}" : "\(.*/\)[^/][^/]*/*$"` || exit 1
        path=`expr "x\`ls -l -d "${path}"\`" : "[^>]* -> \(.*\)"`
        cd "${folder}"
        # If the last path was not a link then we are in the target folder.
        test -n "${path}" || pwd
    done
)

在完整的披露中,......(我找到了这个使者的变量部分)以及在Rich’s sh的技巧中,我也在我自己的答案的披露下披露了他的页面的相关部分。

具体的:

雖然不是嚴格 POSIX 到目前為止, realpath 是一個 GNU 核心應用程式自 2012 年 全公開:我從未聽到它之前,我注意到它在 info coreutils TOC 和立即思考 [連結] 問題,但使用下列功能,如顯示應該可靠,(現在 POSIXLY?),我希望,有效地提供其呼叫者一個絕對來源的 $0:

% _abs_0() {
> o1="${1%%/*}"; ${o1:="${1}"}; ${o1:=`realpath -s "${1}"`}; eval "$1=\${o1}";
> }
% _abs_0 ${abs0:="${0}"} ; printf %s\\n "${abs0}"
/no/more/dots/in/your/path2.sh

另一方面,你可以这样做:

ps ww -fp $$ | grep -Eo '/[^:]*'"${0#*/}"

eval "abs0=${`ps ww -fp $$ | grep -Eo ' /'`#?}"

试试这:

func () {
body here
eval "$1=\${foo}"
}

foo='hello ; rm -rf /'
dest=bar
eval "$dest=$foo"

当然,下面的版本是完全安全的:

foo='hello ; rm -rf /'
dest=bar
eval "$dest=\$foo"