Home > Articles > Operating Systems, Server > Linux/UNIX/Open Source

Reading Man Pages

Man pages (short for manual) provide documentation for many Unix topics and commands. They are often a good reference for beginners, but they are written and maintained by programmers so they vary widely in how useful they can be. Jon Lasser takes you on a handy trip through the peaks and valleys of perusing man pages.
Like this article? We recommend

Like this article? We recommend

Man pages (man is short for manual, of course) are the standard for Unix documentation. They are available online on any Unix system, and some systems even include paper copies of them. While other forms of documentation have begun to supplant man pages, even these substitutes hew fairly close to the same syntax and style. To understand man pages, you have to see them first. In its simplest form, you can display a man page by typing man ManPageIWantToRead at your prompt.

One of the most important commands to learn is logout, because if you don't sign off of the system when you are finished, anybody else can read your files and send mail as you. This is a common problem on multiuser machines, especially at shared workstations or in computer labs at universities. Often, malicious people will send embarrassing or insulting mail from a machine where the legitimate user has forgotten to log out. This, obviously, won't do, so pretend you logged in to a Unix box and typed the one command your guru told you: man logout. Something quite like the following might come up on your screen: 1

LOGOUT(1) Unix Users Guide

logout - exit from a login shell


Terminates the current login shell and ends the associated session.


The first thing to notice about this man page is its header. You should note that it includes the name of the program, a number in parentheses after the program name (the manual section), and the name of the notional manual that "contains" the page. (Of course, man pages aren't real pages bound in a real book, so in reality no manual physically contains the page.)

Below this header, you should notice that the man page is divided into several elements. Some of these segments, such as the name, the synopsis, and the description, should be present in every man page. Others, such as see also might not be present on a given page.

The name segment contains not only the name of the command, as one would assume, but also a very brief description of the purpose of the command. This is because the name is easily searchable, as you'll soon see. The description provided here might not be helpful to beginning users (or at all!), but any search capabilities are better than none.

Although it's not obvious in this case, the synopsis is the most critical portion of the man page: It shows all the modifiers that can be applied to the command. In the case of logout, there are no modifiers: The only thing you can do is type logout. The synopsis has a special, well-defined syntax that I will examine more closely.

The description might or might not be useful. Remember that these pages were written by programmers, who generally can't remember what it was like to be a novice even when they try. In this case, between the name of the command and both the short and long descriptions, it should be possible to puzzle out what the command does.

The name, synopsis, and description are present on nearly every man page. Other common parts include a files portion, which lists files used or referenced by the command, and an authors field, which lists the names and often the email addresses of the responsible parties. Sometimes you'll see a bugs section, which lists known problems with the command. Occasionally there will be a history, which might explain why things were done the way they were done or perhaps describe how this command is different from the older version of the command.

The man page for logout also contains a see also segment, which points at the page for login. Note that, as in the header, there is a parenthesized number. Man pages are grouped into numbered sections, each with its own purpose.

Manual Sections

The Unix manual is divided into ten sections. These are numbered one through nine, plus a section named "n." For non-programmers, the important sections are one and six. Section one contains what are broadly defined as user commands, such as logout, login, and passwd. Section five provides the documentation for a number of games. (In fact, many games have their man pages in the first manual section, but this is one of the many instances of sloppy documentation I warned you about earlier.) Section four or five, depending on what flavor of Unix you have installed, contains descriptions of configuration file formats, such as mail reader configurations. You might find these useful when you want to know how to configure a particular application or service.

Programmers might be interested in sections two and three of the manual, which contain system calls and subroutines, respectively. Other manual sections differ between Unix flavors but are generally reserved for system-level commands and information.

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.


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.


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 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.


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 customer-service@informit.com 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 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.


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