Home > Articles

Creating Symbolic Links

Symbolic links are convenient shortcuts used to link existing files or directories to files or directories with more convenient locations or names. By default, a number of symbolic links are created when Linux is installed:

  • Various shells listed under the /bin directory, such as bsh, csh, and sh, are actually symbolic links to other shells, such as bash or tcsh.

  • The computer's modem device can be a link to /dev/modem instead of /dev/cua1 or /dev/ttyS1.

  • The ex and vi editors are links to the vim text editor.

Linking Files with the ln Command

There are times when you find that it is convenient to have more than one path to the same file. Say that you want to easily be able to execute an application from anywhere, without typing the entire path to the file. You might create a link from /usr/local/bin to the file's executable.

There are two kinds of links in the Linux world: hard links and soft links. They have similar effects but are two very different beasts.

Soft Links

A soft link is a very small file that you create in a directory. The sole content of this file is the path to the file you are linking it to. So if you create a soft link from /home/michael/foo to /usr/local/bin/foo, you could execute the file, /usr/local/bin/foo, and it would behave as if you were executing /home/michael/foo. However, the file in /usr/local/bin/ would be nothing but a set of instructions pointing the shell to the file in /home/michael. Think of it as call forwarding for your shell! Also, keep in mind that if you delete the original file, your soft link will point at nothing and will be totally useless. (Just like if you forward all your calls to your cellular phone but then turn the cell phone off, your calls will have nowhere to go and the call forwarding will be useless.)

Soft links will work across networked file systems, mounted devices, other file systems, and directories.

To create a soft link, use the ln command with the -s (symbolic link) command-line option, with the original filename followed by the name of the desired link:

$ ln -s graphicwithalongname.xcf graphic.xcf 
$ ls -l  
-rw-rw-r--   1 michael    users   16821 Feb 10 15:22  
graphicwithalongname.xcf 
lrwxrwxrwx   1 michael    users       4 Feb 10 15:22  
graphic.xcf-> graphicwithalongname.xcf 

Notice that if you type ls -l, the directory listing for the soft link reflects the file to which it points.

Hard Links

Hard links work a bit differently than soft links. Let's return to the call forwarding analogy. If a soft link is like call forwarding for a phone number, a hard link would be like having multiple phone numbers that point to the same phone.

Every file on your computer is written to a physical spot on your hard drive. That spot is called an inode and inodes each have a number. When you type ls for a directory listing, you are really looking at an index that tells the file system which inode corresponds to each file. If you type ls -i, you will see a directory listing with the inode numbers:

$ ls -i 
1091611 saved-messages  1091701 sent-mail  1091610  
sent-mail-jun-1999 

When you create a hard link, you are just creating another directory listing to point to the same inode. You can create as many hard links on the system to a single file as you would like without taking up any more disk space. If you delete the original file, the second remains because you have not deleted the inode to which it points. The only way you can delete any file on the file system is by deleting all the hard links to that file. If you make changes to the original file, all the links will reflect that change (because they are all pointing to the same inode).

Hard links do not work across networked file systems, partitions, mounted devices, or any other file system. They also do not work for directories. You can only create a hard link to a file on the same disk and partition as the original.

Use the ln command (without the -s option) to create a hard link:

$ ln graphicwithalongname.xcf newgraphic.xcf 
$ ls -l file* 
-rw-rw-r--   2 michael    users    16821 Feb 10 15:22  
graphicwithalongname.xcf 
lrwxrwxrwx   1 michael    users        4 Feb 10 15:22  
graphic.xcf -> graphicwithalongname.xcf 
-rw-rw-r--   2 michael    users    16821 Feb 10 15:22  
newgraphic.xcf 
$ ls -i  
 45146 graphicwithalongname.xcf    45146 newgraphic.xcf 

Notice that both the files in the example above have the same inode number.

Linking Directories with the ln Command

The ln -s command can also be used to create links to often-used directories. (Note you cannot hard link directories.)

$ ln -s /var/http/html/  /home/amy/website

Now, instead of having to type a long pathname when moving files, you can use the following instead:

$ mv *jpg website/

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.

Overview


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information


To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.

Surveys

Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.

Newsletters

If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information


Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.

Security


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.

Children


This site is not directed to children under the age of 13.

Marketing


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information


If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.

Choice/Opt-out


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information


Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents


California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure


Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.

Links


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact


Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice


We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020