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I have added extra directories to $PATH by exporting PATH=/my/dirs:$PATH But I am not sure if I should do the same to MANPATH. Because default MANPATH is empty yet man command works. I found a command called manpath and its manual says If $MANPATH is set, manpath will simply display its contents and issue a warning.. Does this mean setting MANPATH is not the right way to add directories for man command to search for manual pages?

3 Answers 3

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If you simply set MANPATH, it overrides the default and you lose access to the standard man pages. For example, man ls works before setting MANPATH, but does not work afterwards.

To append a search directory without overriding the default, prefix a colon to MANPATH like this:

export MANPATH=":/path/to/custom/man"

Adding the colon gives you access to both the standard system man pages and the custom pages referenced in the MANPATH variable.

This answer brought to you by manpath(1):

If $MANPATH is set, manpath displays its value rather than determining it on the fly. If $MANPATH is prefixed by a colon, then the value of the variable is appended to the list determined from the content of the configuration files. If the colon comes at the end of the value in the variable, then the determined list is appended to the content of the variable. If the value of the variable contains a double colon (::), then the determined list is inserted in the middle of the value, between the two colons.

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While the title specifically mentions the MANPATH variable, I believe what the original author of the question was partly alluding to was whether there is a way to "add" a manpage to the system without touching the MANPATH variable in the first place.

Therefore, in addition to the accepted answer, I would point out that, in a standard configuration, the manpage command also seems to look at directories in your PATH.

I have not come across the relevant documentation for this, but from personal experimentation, I think the way this works is as follows:

Assume you have a directory in your PATH called /dir1/dir2/dir3/dir4.

Then, dir4 as well as its parent (i.e. dir3) will be searched by manpath, and if one of those directories contains a sub-directory called man or share/man, then the 'man' directory in question will be added to the output of the manpath command.

In practice this means that, e.g., if /home/user/.local/bin is in your path, and you also have a directory called /home/user/.local/share/man, any manpages contained there will be picked up. Similarly, if something like /opt/nano/bin is in your path, then /opt/nano/share/man will be picked up.

Note that by "picked up", I mean that the manpath command will include that directory in its output! The content of those directories still needs to be compatible with man for man to pick up valid manpages from within them. In other words, your home/user/.local/share/man directory should contain a man1 directory containing lots of .1 files, a man5 directory containing lots of .5 files, etc, in groff format.

UPDATE: As per the comments below, the manpath man pages now fully document this behaviour as of man-db 2.10.0.

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  • man 5 manpath for the documentation. Jan 19 at 22:57
  • @ReubenThomas thanks Reuben, but that page still doesn't mention the above. The closest thing man 5 manpath hints at is that you can have 'fixed' path-to-manpath conversions. I haven't seen any documentation regarding 'relative' conversions as shown above. Not sure why; it's an incredibly useful mechanism! Jan 20 at 11:48
  • Indeed, and I have filed a bug requesting this documentation: savannah.nongnu.org/bugs/?61862 Jan 20 at 18:55
  • @ReubenThomas excellent! I'll follow it too! :) Jan 20 at 22:51
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    In response to that bug report, there's now a dedicated section for this (manpages.ubuntu.com/manpages/jammy/en/man5/…) and the other manual pages in man-db refer to that. Feb 9 at 0:00
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You should add your custom directories at the end of your PATH:

PATH=$PATH:/my/dirs

This is so your custom directories do not override system binaries and libraries, which could cause a security issue.

You set MANPATH the same way (MANPATH is empty by default):

MANPATH=$MANPATH:/my/dirs

You should not need to set a MANPATH with well behaved packages, so if it is not broken don't fix it. If it is broken, perhaps you are better filing a bug report ;)

Add this to ~/.bashrc:

export PATH=$PATH:/my/dirs
export MANPATH=$MANPATH:/my/dirs
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  • Typo in the second statement? MANPATH=$MANTPATH:/my/dirs Maybe should be: MANPATH=$MANPATH:/my/dirs
    – kevinarpe
    Nov 11, 2013 at 9:25
  • What do you mean by "well behaved packages"? I have a whole set of tools that are not installed in the usual places (HPC clusters often put things in /opt). How should they register their man pages without using $MANPATH?
    – i_grok
    Mar 15, 2014 at 15:30
  • "well behaved packages" are written to use standard paths and environmental variables. Poorly behaved packages use non standard, at least to Ubuntu, paths such as /opt or do not use environmental variables and thus lead to your observation " I have a whole set of tools that are not installed in the usual places (HPC clusters often put things in /opt)"
    – Panther
    Mar 15, 2014 at 16:55

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