The FreeBSD Diary

Providing practical examples since 1998

Creating a symbolic link

This article shows you how to create a symbolic link.

You might also want to see Linking to other directories with Apache.

What is a symbolic link?

A symbolic link is a way of saving disk space when the same file structure must exist in two places. It's also a way of creating a short cut to another place. These shortcuts are used quite often on ftp servers. For example, if you look at your typical FreeBSD ftp server, you might see something like this:

ftp> cd /pub/FreeBSD
250 CWD command successful.
ftp> ls 3*
227 Entering Passive Mode (203,97,33,7,193,160)
150 Opening ASCII mode data connection for /bin/ls.
lrwxrwxrwx 1 0 1 25 May  9 22:29 3.1-RELEASE -> releases/i386/3.1-RELEASE
lrwxrwxrwx 1 0 1 25 May  9 22:29 3.1-STABLE -> releases/i386/3.1-RELEASE
lrwxrwxrwx 1 0 1 25 May 18 10:03 3.2-RELEASE -> releases/i386/3.2-RELEASE
226 Transfer complete.

You can see that the releases actually exist within a subdirectory. In case, the links are relative to the current path.

/home

You should see man ln for full details. But here are a few practical examples.

The following demonstrates that /home is a shortcut for /usr/home.

# cd /
# ls -ld home
lrwxr-xr-x  1 root  wheel  9 Jun 20 19:28 home -> /usr/home

This link could be created with:

# ln -s /usr/home /home

In this case the links are absolute, not relative as in the ftp server example.

Files

You can also create a symbolic link with a file. I'll show you some FreeBSD examples from /dev and in /etc.

# cd /dev
# ls -lt | grep ">"
lrwxr-xr-x  1 root  wheel           10 Jul  5 11:47 vga -> /dev/ttyv0
lrwxr-xr-x  1 root  wheel           12 Jun 20 19:15 log -> /var/run/log
lrwxrwxr-x  1 root  wheel            5 Jun 20 19:05 wcd0c -> acd0c
lrwxrwxr-x  1 root  wheel            6 Jun 20 19:05 rwcd0c -> racd0c
lrwxrwxr-x  1 root  wheel            6 Jun 20 19:05 rwcd0a -> racd0a
lrwxrwxr-x  1 root  wheel            5 Jun 20 19:05 wcd0a -> acd0a
# cd /etc
# ls -lt | grep ">"
lrwxrwxrwx 1 root wheel 23 Jun 20 18:58 termcap -> 
                                            /usr/share/misc/termcap
lrwxrwxrwx 1 root wheel 13 Jun 20 18:58 rmt -> /usr/sbin/rmt

To create a symbolic link in your home directory from such as the termcap link above, you could do this:

# ln -s /usr/share/misc/termcap /etc/termcap