A symlink is a symbolic link, this is, an alias or shortcut to a program or file.
It's a special file existing in the FileSystem space which just points to another file (or directory). If you access the symlink from an application, it appears transparent for the application and you will really access the file or directory which the symlink is pointing to.
It is a special kind of file that contains a pathname to another file. The file type entry in the file's inode indicates that it is a symbolic link. When you attempt to access a symbolic link with a text editor or other program, the kernel redirects the program to the file indicated by the symbolic link's pathname. Unlike hard links, symbolic links can be made across different filesystems. Use the ln command with the -s option to create a symbolic link.
The symlinks utility performs maintenance on symbolic links. Symlinks checks for symlink problems, including dangling symlinks which point to nonexistent files. Symlinks can also automatically convert absolute symlinks to relative symlinks. Install the symlinks package if you need a program for maintaining symlinks on your system.
Note: If you delete the symlink, you are only deleting the symlink! Not the file or directory it was pointing to!
Although a symlink shows up with file permissions and user/group ownerships, the access rights are only determined by its target permissions and user/group ownerships!
You create a symlink with
ln -s <destination file or directory> <name of the symlink>