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Is there a way to follow the links mentioned in a man page? For example, here's the man page for ps; how do I access the link marked in red?

Screenshot of the ps man page

  • 1
    Also, I see that man is an interface to the on-line reference manuals which (if I am not wrong) means it should be pulling all the info from some webpage on the internet, right? So, anyone has a clue as to what the http:// link is? – its_me Aug 5 '11 at 20:23
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    Here “on-line” means “on the computer” (as opposed to “on paper”), not “on the Internet”. – Gilles Aug 5 '11 at 21:45
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    "On-Line": You might remember those "Adventure" Quest games for PC that were put out by a company (then) named Sierra On-Line. man pages: The best way to browse man pages is to use your editor. That way, navigating, searching (etc.) the text will be so smooth as every shortcut is in your muscle-memory since long. Also, say you work on a programming project - you could copy from man pages into your code. Nothing less than seamless interaction. Check out this and my comment to @Gilles ' answer. – Emanuel Berg Mar 6 '13 at 22:46
48

Man pages date back to Unix First Edition. While hypertext had been invented, it was still in infancy; the web was two decades away, and the manual was an actual printed book, often with one command per page if they fit (that's why they were called pages).

The format used for manual pages has evolved somewhat since then, but most pages aren't really designed for hypertext, and the default man program doesn't support it (it's just a plain text viewer, with hacks to support some basic formatting). There are however man page viewing programs that reconstruct some hyperlinks, mainly links to other man pages, which are traditionally written in the form man(1) where man is the name of the man page and 1 is the section number:

You can browse the manual pages of several operating systems, converted to HTML by man2html or similar tools, on a number of sites online, for example:

Some time after man pages had become the established documentation format on unix and some time before the web was invented, the GNU project introduced the info documentation format, more advanced than man while sticking to simple markup designed for text terminals. The major innovation of info compared to man was to have multi-page documentation with hyperlinks to other pages. Info is still the prefered documentation format for GNU projects, though most Info pages are generated from a Texinfo source (or sometimes other formats) that can also generate HTML. When info documentation for a program exists, it's often the main manual, while the man pages only contain basic information about command line arguments.

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    Great answer! Also worth mentioning is that there is another mode for man pages in Emacs, the one (at least I) get by just M-x man (and C-h v mode-name is Man): at least in one aspect, it is superior to WoMan because it displays tables (screenshot). Of course, it is hyperlinked as well. – Emanuel Berg Mar 6 '13 at 22:38
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    The info program user interface feels just wrong and counter-intuitive. I haven't seen anyone using that. – Pavel Šimerda Jan 16 '18 at 1:53
  • @PavelŠimerda> The info program user interface feels just wrong and counter-intuitive. < Emm, compared to what? To less(1) (which is default pager for man(1) in GNU) — that thing, where you have to recall how to scroll back, since <backspace> is not bound (and <pgup> might not work at all)? The primary key is b, by that way. To a user of which interface paradigm this might be intuitive? – Dmitry Alexandrov Feb 10 '18 at 22:40
  • @PavelŠimerda> I haven't seen anyone using that. < Always use info(1) for reading manpages when got locked in a text terminal for the exact reason, that unlike less(1) it does convert dumb page(N) links into hyperlinks. Was quite suprised that is was not mentioned in Gilles’ answer in that quality. – Dmitry Alexandrov Feb 10 '18 at 22:41
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First of all, it's not a link. It's just an underline. Man pages are just text documents with a little bit of simple formatting that a terminal can handle. The underline is just a highlight, there is no "link" involved.

The normal man command is just a text formatter. In fact the man command doesn't even display the text, man just formats the information stored in the man page file[1] and sends the formatted output to another program (usually less) that displays the formatted output to the screen. These display programs have no concept of links.

There are some special documentation readers that might be able to look at formatting like that and make an educated guess that such a highlight might indicate that there is a related man page that could be pulled up and create a link, but I don't know which ones do. Perhaps pinfo?

If you want web like formatting with hyperlinks you can find almost any UNIX man page online with links added in. Try typing man [anything] into google and you will almost certainly get one in the first couple hits.

In the case of your example, the visual highlighting is a clue that that is another program name that has it's own man page that you can easily pull up. Try man 1 top. The 1 indicates the section of the man pages to look in. See this question for an explanation of the sections: What do the numbers in a man page mean?


[1] If you open the man page file in a text editor, you will see the raw man page that is not formatted for easy reading. The raw man page is written in a markup language called troff. For more information on troff and how to write a man page see: https://liw.fi/manpages/ .

  • Any idea why it is man 1 top ?? I mean it should be something like ps 1 top because I found the link on the man page for ps. "man 1 top" doesn't make sense to me. Please clarify. – its_me Aug 5 '11 at 20:20
  • There are also some resources that make man pages available on the internet, with references replaced by href's, which are clickable. – gabe. Aug 5 '11 at 20:22
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    If you want to follow top(1) "link", you need to open top manual page from 1st section. For more information about sections see man(1). ps 1 top does not makes any sense, since you'll just run ps command with some strange to it params. – rvs Aug 5 '11 at 20:23
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    @Aahan it's man 1 top because you want to see the manual page for the top command in the 1st section of the online manual pages. The reference top(1) means just that, top in the 1st section of the manual pages. To see that, you type "man 1 top" at the prompt. See "man man" – gabe. Aug 5 '11 at 20:24
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    @Aaran: The "sections of the manual cover different topics. Section 1 is user commands (stuff you type at the prompt) section 2 is system calls and so on. Some strings appear n more than one section. On the machine I am on right now readlink appears in section 1 and section 2 and printf in sections 1 and 3. If you just type man command, man trys sections in numeric order and displays the first it finds, or you can be specific with man # command, which you have to do to get the documentation for the readlink system call. – dmckee Aug 6 '11 at 14:26
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This is very late reply but use w3mman. w3mman is the system’s manual pager by w3m.

https://linux.die.net/man/1/w3mman

You can try it by installing w3m package. I believe this package is registered in the software repositories of most of major Linux/UNIX distributions and Cygwin.

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    A late reply that adds some answer to the question that is not mentioned yet, it never a problem! Welcome at Unix&Linux StackExchange! – Bernhard Dec 14 '12 at 9:48
  • w3mman is also provided with the default Macports w3m installation. It's great :) Thanks! – sampablokuper Sep 8 '14 at 0:58
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Let me try to interpret your question a bit more in a sense in which I try to follow your workflow. What you probably would like to have is a key combination within a man page that leads you directly to the underlined commands you are reading about. So, not having to install something else, nor opening up another console and forgetting the exact syntax for example.

This simplest solution is the exclamation mark (if you are using less to display the man pages) and you want to go to the underlined top:

!man top

Or

!man 1 top

You will have to close them all by pressing q multiple times. Note also that this won't work if LESSSECURE=1 is set as environmental variable which would make run less in secure mode and not allow you to use !. It will tell you something like "Command not available".

1

Although w3mman is a solution to follow links, does not use all the screen (at least on ubuntu 12.10)

I prefer to use:

$ sudo su -
# apt-get install w3m man2html
# exit
$ alias man=' hman -P w3m'

add the last command to ~/.bash_aliases or similar startup script to get it on every session.

The -P w3m is because first browser to hman is lynx or sensible-browser but I prefer w3m

hman is a tool bundled on html2man. See this

If exit with confirmation is annoying to you, as to me is use this

  • My mistake, the package must be html2man – albfan Mar 7 '13 at 17:32
1

Specifically for Ubuntu, there is Yelp. It's installed by default and is by default able to display manual pages, although the invocation to do so, is not the same as that of the man command; an alias or a shell function can work around the latter point (depends on your shell).

yelp 'man:exit'

It will default to a section in a way I don't know. Reminder: to get the sections list for a manual topic, use whatis, as in whatis exit.

To request Yelp to display a manual page from a specific section, say 2, do:

yelp 'man:exit(2)'

Issues: yelp has bugs and be prepared to get multiple errors output when invoking it from the command line. There also, an alias or a custom shell function can help redirecting all errors to /dev/null

1

Like they said, it wasn't designed for it.

You can use info man and then hit enter once you're under SEE ALSO section on your item.

info - read Info documents

1

I have a (couple of) hack(s).

hack 1

Put this in your ~/.bashrc or your ~/.zshrc

function man(){
    for arg in "$@"; do
        vim -c 'execute "normal! :let no_man_maps = 1\<cr>:runtime ftplugin/man.vim\<cr>:Man '"${arg}"'\<cr>:wincmd o\<cr>"'
    done
}

Screenshot..

manual in vim screenshot

Asciinema..

https://asciinema.org/a/130131

Now..

  1. when you type man vim, for example, it will open up this man page in vim

    • if you type man man vim, for example, it will first open man's manual and after you exit vim, it will open vim's manual
  2. when you press K (that's capital k) when you are on another man page at the bottom (the SEE ALSO section), you will jump to this manual (unfortunately inside of a less pager -- this is because we have let no_man_maps = 1; if you don't do that, then vim will force q to be :q and you will be unable to record a macro easily, and vim may behave wonkily in other ways).

    • exiting this second manual you have entered will bring you back to the previous manual you were viewing
  3. you get very pretty syntax highlighting since you have loaded ftplugin/man.vim and the ft is (automatically) set to man.

  4. you can copy and paste, navigate freely in vim, and even modify the buffer and :w ~/usefulfile. You can do everything you would normally do in vim, including record macros, yank to clipboard with "+y (if you have +clipboard), etc, etc.

I find it much nicer than less.

The only minor setback I have found (which still exists if you use less as your pager) is if you want to have multiple manuals open in one vim session. I don't really see a way to do this.

A few notes:

  1. if you try to save the buffer, you will get E382: Cannot write, 'buftype' option is set

    • I like that you cannot save as it prevents accidentally saving it
  2. you can still save like :w /tmp/man.man

    • if you save it with a .man extension, then opening it up will set the filetype to man for you
    • if you do not save it with a .man extension, you can just set the ft to man by running :set ft=man
  3. if you need to do things when opening up man pages you can use autocmd VimEnter *.~ echom 'hooray, we are using vim for man pages!', for example.

  4. I have put the following in my vimrc so that I can press K to try to open manual, and then press G to go back to previous manual:


augroup man
    autocmd!
    autocmd VimEnter *.~ nnoremap B :execute "normal! `Z"<cr>
    autocmd VimEnter *.~ nnoremap <buffer> K :execute "normal! mZyiw:Man \<lt>c-r>\"\<lt>cr>"<cr>
augroup END

hack 2

put this in your ~/.bashrc or ~/.zshrc

function man(){
    declare -a args
    for arg in "$@"; do
        command man "$arg" > "/tmp/${arg}.man"
        args+=("/tmp/${arg}.man")
    done
    vim "${args[@]}"
}

Screenshot..

multiple manuals in vim

Asciinema..

https://asciinema.org/a/9Q6Si90Pi46cDVUknxFxfIwsv

This solves problem that hack 1 and less face (now you can view multiple manuals in one buffer), but it is less elegant.

Notes:

  1. IMPORTANT if you want hack2 to work, then you must put :let no_man_maps = 1 in your ~/.vimrc. This is because vim will source .../vim80/man.vim and q will be forcibly remapped to :q.

  2. there is more clean up involved (now you store every manual to /tmp/*.man)

  3. you can now, however, view multiple man pages in one session, as noted above

  4. if you press K, you will still open a new vim session, however

    • if you want you can bind an autocmd (using an autocmd like the one above) to do something like autocmd VimEnter man.~ nnoremap <buffer> K :execute "normal! Byt(:silent !man \<c-r>\" > /tmp/\<c-r>\".man\<cr>:edit /tmp/\<c-r>\".man\<cr>" or something crazy like that (untested)
  • apologies for badly colored asciinema. The colors look a lot nicer in my terminal. – Dylan Jul 22 '17 at 23:19
0

I was able to use the --html argument to man in order to open it in the browser defined by $BROWSER environment variable, so:

BROWSER=google-chrome man ps --help

I'm using Fedora. Not sure if this works for your distro, please test and report in comments.

  • The option seems recognized on Ubuntu 12.04, but it fails. – Hibou57 Aug 12 '14 at 8:08
  • OK, the package groff needs to be installed. The groff command may be there while the package of the same name is not (the command comes with groff-base, not the full groff package). I do man --html="surf file%c//%s" <command>, and it's fine. There is very‑very limited hypertext though :-/ . – Hibou57 Aug 12 '14 at 8:45

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