Unix Create a Symbolic Link

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How do I create a symbolic links under Linux or Unix like operating systems using command line options?

You need to use the ln command. It is a standard Unix / Linux / BSD command to create links to files. There are two types of links under UNIX, hard and soft link:

Hard link vs. Soft link in Linux or UNIX

[a] Hard links cannot links directories ( cannot link /tmp with /home/you/tmp)

[b] Hard links cannot cross file system boundaries ( cannot link /tmp mounted on/tmp to 2nd hard disk mounted on /harddisk2)

[c] Symbolic links refer to a symbolic path indicating the abstract location of another file

[d] Hard links, refer to the specific location of physical data.

UNIX create a symbolic link command

To create a symbolic link, enter:
$ ln -s {/path/to/file-name} {link-name}
$ ln -s /shared/sales/data/file.txt sales.data.txt
$ vi sales.data.txt
$ ls -l sales.data.txt

How do I delete a symbolic link?

To delete a link, enter:
$ rm {link-name}
$ rm sales.data.txt
$ ls -l
$ ls -l /shared/sales/data/file.txt

If you delete the soft link itself (sales.data.txt) , the data file would still be there ( /shared/sales/data/file.txt ). However, if you delete /shared/sales/data/file.txt, sales.data.txt becomes a broken link and data is lost.

UNIX create a hardlink command

To create hard link, enter (without the -s option):
$ ln {file.txt} {hard-link}
$ ln /tmp/file link-here

How do I delete a hard link?

You can delete hard link with the rm command itself:
$ rm {hard-link}
$ rm link-here

If you delete a hard link, your data would be there. If you delete /tmp/file your data still be accessible via link-here hard link file.

See also:

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

5 comment

  1. I am trying to create a hard link to PHP file after installation of PHP4 as a CGI .
    My Current directory is clients cgi-bin and want to create a link to usr/local/php4/bin/php but getting following error:

    ln: creating hard link `php’ to `/usr/local/php4/bin/php’: Invalid cross-device link

  2. I could never get the order of the two things in “ln -s X Y” right, and ended up clobbering Ys with dangling links to X. So I wrote this little sanity-checker wrapper around it: lns.
    It does stuff like making sure that your link won’t overwrite anything, and that it’s a link to something that already exists. Just common sense, but sense that I didn’t have.

    lns: http://interglacial.com/~sburke/pub/lns.html

    I’ve been using it for ten years, and I think it’s the most useful program I’ve ever written. (crontab2english is a runner-up, people tell me)

  3. If you want to create a symbolic link for multiple files under one directory e.g. want to have all jar files of java to ant lib you can use this feature of linux. This will solve your purpose as well as save the space with reduced redundancy.
    One can use for loop to create a sym link of multiple files of a directory as below,

    # for F in `ls /usr/share/java/ext/*.jar`; do `ln -s $F  /usr/share/ant/lib/`basename $F /usr/share/java``; done  
    
  4. Here is a youtube comment I made based on solving a lua-5.2.3 update issue on CentOS 6.5. The issue here is that your symbolic link tutorial was the key to solving my update issue with lua-5.2.3.

    So here is a dilemma I ran into with CentOS 6.5. # lua -v returns lua-5.1.4 while the latest version is now lua-5.2.3. lua.org/ makes no mention of how to deal with updating the old lua version. Here is what works for me on CentOS 6.5:
    1. sign in as administrator on your linux machine
    2. # cd /opt/
    3. # curl -R -O http://www.lua.org/ftp/lua-5.2.3.tar.gz
    4. # tar zxf lua-5.2.3.tar.gz
    5. # cd lua-5.2.3
    6. # make linux test
    7. # lua -v
    8. Note: If it returns lua-5.1.4 then
    9. # which lua /* /usr/bin/lua is returned */
    10. # rm /usr/bin/lua /* removes old installation */
    11. # ln -s /opt/lua-5.2.3/src/lua /usr/bin/lua /* symbolic link to version 5.2.3 */
    12. lua -v /* should return lua-5.2.3 */
    12. which lua /* should return /usr/bin/lua */
    Since this latest .rpm is still lua-5.1.4 yum install didn’t do an update. Hope this is of help to some.

    Thanks much.

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