Change width of man command ouput

Question

I use Guake terminal emulator a lot. It's the best thing since sliced bred IMO.

But one thing has been bugging me, when I want to read man pages the default width of the output is the width of the terminal windows, which in my case is always full screen so it's a bit difficult to read.

Is there a way I can make the default width of the output of man command a, pleasant to read, 80 characters?

The man page for man has this part:

   MANWIDTH
          If  $MANWIDTH  is set, its value is used as the line length for which manual pages should be formatted.  If it is not set,
          manual pages will be formatted with a line length appropriate to the current terminal (using an ioctl(2) if available, the
          value  of  $COLUMNS,  or  falling  back  to 80 characters if neither is available).  Cat pages will only be saved when the
          default formatting can be used, that is when the terminal line length is between 66 and 80 characters.

But I cant figure out where to change it.

I tried adding the line:

MANWIDTH 80

to /etc/manpath.config and ~/.bashrc, but with no result.

Answer 1

As pointed out in other answers, setting and exporting MANWIDTH properly is the way to go.

I would avoid hardcoding it, or else it will overflow / have ugly linebreaks when your terminal emulator window is more narrow than that value:

NAME
       grep, egrep, fgrep - print lines that match
 patterns

SYNOPSIS
       grep [OPTION...] PATTERNS [FILE...]
       grep [OPTION...] -e PATTERNS ... [FILE...]
       grep [OPTION...] -f PATTERN_FILE ... [FILE.
..]

DESCRIPTION
       grep  searches  for  PATTERNS  in  each  FI
LE.  PATTERNS is one or more
       patterns separated by newline characters, a
nd  grep  prints  each  line
       that  matches a pattern.  Typically PATTERN
S should be quoted when grep
       is used in a shell command.

Here's what I use, in a handy alias:

alias man='MANWIDTH=$((COLUMNS > 80 ? 80 : COLUMNS)) man'

This sets MANWIDTH to 80 if the terminal window is wider than that, and to COLUMNS (the current width of the terminal window) if it is more narrow.

Result in a wide window:

NAME
       grep, egrep, fgrep - print lines that match patterns

SYNOPSIS
       grep [OPTION...] PATTERNS [FILE...]
       grep [OPTION...] -e PATTERNS ... [FILE...]
       grep [OPTION...] -f PATTERN_FILE ... [FILE...]

DESCRIPTION
       grep  searches  for  PATTERNS  in  each  FILE.  PATTERNS is one or more
       patterns separated by newline characters, and  grep  prints  each  line
       that  matches a pattern.  Typically PATTERNS should be quoted when grep
       is used in a shell command.

Result in a narrow window:

NAME
       grep,  egrep, fgrep - print lines that
       match patterns

SYNOPSIS
       grep [OPTION...] PATTERNS [FILE...]
       grep  [OPTION...]  -e   PATTERNS   ...
       [FILE...]
       grep  [OPTION...]  -f PATTERN_FILE ...
       [FILE...]

DESCRIPTION
       grep searches  for  PATTERNS  in  each
       FILE.    PATTERNS   is   one  or  more
       patterns    separated    by    newline
       characters,  and grep prints each line
       that  matches  a  pattern.   Typically
       PATTERNS should be quoted when grep is
       used in a shell command.

Answer 2

That's an environment variable.

Try:

MANWIDTH=80
export MANWIDTH
man bash

If you want that set permanently then you can add those first two lines to your shell session startup scripts or similar.