bash - 如何从脚本本身获取 Bash 脚本所在的目录？

Question

如何获取 Bash 所在目录的路径脚本位于内部那个脚本？

我想使用 Bash 脚本作为另一个应用程序的启动器。我想将工作目录更改为 Bash 脚本所在的目录，这样我就可以对该目录中的文件进行操作，如下所示:

$ ./application

Answer 1

#!/usr/bin/env bash

SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )

是一个有用的单行代码，无论从何处调用它，它都会为您提供脚本的完整目录名称。

只要用于查找脚本的路径的最后一个组成部分不是符号链接(symbolic link)(目录链接就可以)，它就可以工作。如果您还想解析指向脚本本身的任何链接，则需要多行解决方案:

#!/usr/bin/env bash

SOURCE=${BASH_SOURCE[0]}
while [ -L "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
  DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
  SOURCE=$(readlink "$SOURCE")
  [[ $SOURCE != /* ]] && SOURCE=$DIR/$SOURCE # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
done
DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )

最后一个可以与别名、source、bash -c、符号链接(symbolic link)等的任意组合一起使用。

注意:如果您在运行此代码段之前cd 到不同的目录，结果可能不正确!

另外，注意 $CDPATH gotchas和 stderr 输出副作用，如果用户巧妙地覆盖 cd 以将输出重定向到 stderr(包括转义序列，例如在 Mac 上调用 update_terminal_cwd >&2 时)。在 cd 命令末尾添加 >/dev/null 2>&1 将处理这两种可能性。

要了解它是如何工作的，请尝试运行这个更详细的表单:

#!/usr/bin/env bash

SOURCE=${BASH_SOURCE[0]}
while [ -L "$SOURCE" ]; do # resolve $SOURCE until the file is no longer a symlink
  TARGET=$(readlink "$SOURCE")
  if [[ $TARGET == /* ]]; then
    echo "SOURCE '$SOURCE' is an absolute symlink to '$TARGET'"
    SOURCE=$TARGET
  else
    DIR=$( dirname "$SOURCE" )
    echo "SOURCE '$SOURCE' is a relative symlink to '$TARGET' (relative to '$DIR')"
    SOURCE=$DIR/$TARGET # if $SOURCE was a relative symlink, we need to resolve it relative to the path where the symlink file was located
  fi
done
echo "SOURCE is '$SOURCE'"
RDIR=$( dirname "$SOURCE" )
DIR=$( cd -P "$( dirname "$SOURCE" )" >/dev/null 2>&1 && pwd )
if [ "$DIR" != "$RDIR" ]; then
  echo "DIR '$RDIR' resolves to '$DIR'"
fi
echo "DIR is '$DIR'"

它会打印出如下内容:

SOURCE './scriptdir.sh' is a relative symlink to 'sym2/scriptdir.sh' (relative to '.')
SOURCE is './sym2/scriptdir.sh'
DIR './sym2' resolves to '/home/ubuntu/dotfiles/fo fo/real/real1/real2'
DIR is '/home/ubuntu/dotfiles/fo fo/real/real1/real2'