File System - ( Symbolic | ln | Soft) link - File Alias - Symlink - Junction - Reparse Points

About

A soft link, symlink or a symbolic link is a file that redirects (link) to another file.

It's the alias functionality of a file system.

Unlike a hard link, a symbolic link can link to any file on any computer.

Operating System

Linux

Creation

They are created with the ln command.

They are created with the ln command and the -s parameter:

ln -s /the/full-real/file/path /the/sym/link/file/path
ln -s /the/full-real-path/to-directory /the/symlink/directory/path

ln -s /etc/dbora /etc/rc.d/rc2.d/S99dbora

See canonical/real path:

readlink -f /the/sym/link/file/path

Remove Without trailing slash:

• unlink

unlink /the/sym/link

• or remove

# rm /the/sym/link/ <- Bad
rm /the/sym/link

Target

Target of symlink can be:

• a path to:
  • a file descriptor
  • a regular file
• a pipe (pipe:[2333507])

Windows

Symlink are also known as junction on Windows.

Dos

mklink

Creates a symbolic link.

MKLINK [[/D] | [/H] | [/J]] Link Target

        /D      Creates a directory symbolic link.  Default is a file
                symbolic link.
        /H      Creates a hard link instead of a symbolic link. (Works only with files ? See option /D)
        /J      Creates a Directory Junction.
        Link    specifies the new symbolic link name.
        Target  specifies the path (relative or absolute) that the new link
                refers to.

Example for:

• a file

mklink  targetSymlink sourceFile 
REM with a php ini file
mklink  C:\php-7.2.6-Win32-VC15-x64\php.ini D:\repo_backup\php.ini

symbolic link created for C:\php-7.2.6-Win32-VC15-x64\php.ini <<===>> D:\repo_backup\php.ini

• A directory

mklink  /D symlink directory 

REM example for the preferences directory of Eclipse
mklink /D "D:\workspace\.metadata\.plugins\org.eclipse.core.runtime" "D:\svn\Config\Eclipseorg.eclipse.core.runtime"

symbolic link created for D:\workspace\.metadata\.plugins\org.eclipse.core.runtime <<===>> D:\svn\Config\Eclipse\org.eclipse.core.runtime

• List: the dir command show the target of symbolic links (called Reparse Points)

dir /a:l

/A          Displays files with specified attributes.
  attributes   D  Directories                R  Read-only files
               H  Hidden files               A  Files ready for archiving
               S  System files               I  Not content indexed files
               L  Reparse Points             -  Prefix meaning not

Powershell

• GetFinalPathNameByHandleA function - Retrieves the final path for the specified file.

Security and Developer Mode

On Windows, you can activate Developer Mode to allow non-admin users to create symlinks by following this instructions.

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