Publishers of technology books, eBooks, and videos for creative people

Home > Articles > Apple > Operating Systems

This chapter is from the book

Shell Aliases

Shell aliases are shortcut names for commands. Each alias consists of one word (or even one letter) that you can use instead of a longer command line. For example, you may find yourself using the command ls -F a lot. You can easily make a shortcut for that command: lf, for example. So when you use lf where the shell expects a command, then the shell will substitute ls -F.

To see all your current aliases:

  • alias

    The alias command with no arguments displays all your current aliases. The first item on each line is the alias (which must always be a single string, with no spaces), and the rest of the line is the full command for which the alias is a shortcut. Figure 7.9 shows the default aliases for the tcsh shell. You can see that the alias l is a shortcut for the command ls -lg. The first word on each line is the name of the alias; the rest of the line is what gets executed when the alias is used.

    Several of the aliases are more complicated. The aliases in Figure 7.9 are for the tcsh shell, and several of them make use of specific advanced features of that shell (see man tcsh for all of the available features). For example, the alias in Figure 7.9 called line expects two arguments (indicated by !:1 and !:2), while the alias called ll takes all of its arguments (indicated by !*) and inserts them into the middle of a command line.

    Figure 7.9Figure 7.9 Using the alias command to see all currently set aliases. Shown are the default aliases for the tcsh shell.

You can create aliases at the command line or by adding them to a configuration file.

Aliases created at the command line are only in effect for as long as you use that shell—that is, they disappear when you close that Terminal window. If you want an alias to always be available, you must put it in a con-figuration file.

To create an alias in tcsh or csh:

  1. alias lf 'ls -F'

    This will create an alias called lf, which the shell will translate into ls -F whenever you use lf as a command. Make sure to enclose the last argument in quotes, either single or double, so that everything after the alias name is treated as a single entity.

    Check to see that the alias is set:


    The line

    lf ls -F

    should be included in your aliases now.


    • If you want to have an alias use arguments from the command line inside the alias definition, you can use !:1 for the first argument, !:2 for the second, and so on. But you must escape the ! in the alias definition. So to define an alias called myword that takes its first argument and searches for it inside the file ~/mydictionary, you would use

      alias myword 'grep \!:1 ~/ 
      → mydictionary'
    • You could use that alias in this way:

      myword banana

      as a shortcut for

      grep banana ~/mydictionary 

To create an alias in tcsh (or csh) that is set every time you start a shell:

  1. Open your ~/.tcshrc file (for the csh shell use ~/.cshrc).

  2. Add a line with the alias

    alias lf 'ls -F'
  3. Save the file.

  4. Quit the editor.

    The new alias will be set for the next shell you start.

  5. Open a new Terminal window to check that the alias is set:


    You should see your new alias in the resulting list.


    A set of example aliases for the tcsh shell are contained in the file /usr/share/ tcsh/examples/aliases.

To create an alias in bash:

  1. alias lf='ls -F'

    Note that there are no spaces before or after the equal sign.

  2. alias

    The shell shows all your current aliases, including the one you just created. As with the tcsh shell, bash aliases created at the command line will disappear when you exit the shell.

To create an alias in bash that is set every time you start a shell:

  1. Open your ~/.bash_profile file.

  2. Add a line with the alias—for example, alias lf='ls -F'

  3. Save the file.

  4. Quit the editor.

    The new alias will be set for the next shell you start.

  5. Open a new Terminal window to check that the alias is set:


    You should see your new alias in the list:

    alias lf='ls -F'

Shell functions

Unlike aliases in the tcsh shell, aliases in bash cannot have command-line arguments included in them. However, bash allows you to create shell functions, which can make use of their arguments.

The term shell function applies to series of shell command lines. This is similar to an alias, except that a shell function can be many lines long, and you may use the special variables $1 for the first argument, $2 for the second, and so on.

Shell functions should be defined in your ~/.bash_profile.

To create a shell function in bash:

  1. Open your ~/.bash_profile.

    The entire function you will be entering is shown in Figure 7.10. This sample function looks up a word in two different files that make up a dictionary.

    Figure 7.10Figure 7.10 Code listing of a bash shell function.

  2. Enter the first line of the new function. In this example you are creating a function called "word":

    word () {

    The parentheses tell bash that this is a function definition. The bracket ({) marks the beginning of the commands in the function.

  3. Enter the body of the function:

    grep $1 /usr/share/dict/web2 
    grep $1 /usr/share/dict/web2a

    Notice that the function can have more than one line of commands.

    The $1 is a variable that will be replaced with the first argument when you use the function in a command line. (Read the file /usr/share/dict/README for a description of the web2 and web2a files.)

  4. Finish the function definition with a }. Double-check that what you entered looks like Figure 7.10.

  5. Save the file.

  6. Quit the editor.

    The new function will be in effect with the next Terminal window you open.

  7. Open a new Terminal window.

  8. Test the function by trying it on the command line. If you are using the example function from Figure 7.10, then the first argument you supply is used in the function. The function searches two different files for its first argument.

  9. word auspic

    You should get the output shown in Figure 7.11. Your new shell function, word, takes its first argument (the $1 in the function) and searches for it in the two files. The function is really a short shell script (see Chapter 9, "Creating and Using Scripts") but is part of your personal shell configuration.

    Figure 7.11Figure 7.11 Using the new shell function to look up "auspic" in the dictionary.

Peachpit Promotional Mailings & Special Offers

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


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about Peachpit 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.


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.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email

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.


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


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


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 and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by Adobe Press. 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:

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

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.


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