Ygtjki

With the example command

man apropos > outputfile

a text file is generated which contains the formatted man page of apropos (with some little differences with respect to man apropos directly printed on screen, such as bold characters).

But I would like to manually set the maximum line width of the generated output file, so that all the paragraphs will be justified to that width.

man pages are created through groff: for example, I tried to put .ll 50 before a paragraph of the original .gz man source text file, but it is trivial if I need to work on several man pages. Moreover not all the characters are recognized:

apropos.1:45: warning: can't find character with input code 195
apropos.1:45: warning: can't find character with input code 168
apropos.1:47: warning: can't find character with input code 178
apropos.1:131: warning: can't find character with input code 169

So, I wonder if a more straightforward method exists. How to modify the maximum line width, during the creation of an outputfile? Is there some specific command?

Edit:

(All the following considerations are about Ubuntu 18.04: I can no more test them in previous versions, included the 14.04 of the above question.)

As regards a one-line temporary solution, if MANWIDTH has not been already exported with a custom value, there is no difference between

$ MANWIDTH=60 man apropos > outputfile

and

$ COLUMNS=60 man apropos > outputfile

The first one, using MANWIDTH, is however better in principle.

Edit 2 (not strictly related to the question):

To make instead a permanent width setting to be applied to any manpage printing, it is necessary to export the desired value of the variable. With:

$ export MANWIDTH=60
# zero or more additional lines
$ man apropos > outputfile

man apropos will be printed with the same width regardless of any terminal window resizing. Instead,

$ export COLUMNS=60
# zero or more additional lines
$ man apropos > outputfile

will provide the same result as before only if the terminal window is not resized between export and man <page> > outputfile.

Use the MANWIDTH environment variable:

MANWIDTH=60 man apropos > apropos.txt

The manpage for man 2.7.4 says:

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 the value of $COLUMNS, an ioctl(2) if available, or falling back to 80 characters if neither is available).

That is, it overrides both COLUMNS and the ioctl value. I prefer to not rely on modifying COLUMNS (although it does work here) since its value is updated dynamically every time the window size changes.

Using MANWIDTH instead of COLUMNS also allows you to make the change permanent by adding a line such as export MANWIDTH=60 to your shell startup file.

Try setting the COLUMNS environment variable. Works for me with man from mandb 2.7.0.2 on Debian with groff 1.22.3.

$ COLUMNS=60 man apropos | head
APROPOS(1) Manual pager utils APROPOS(1)



NAME
 apropos - search the manual page names and descrip‐
 tions

SYNOPSIS
 apropos [-dalv?V] [-e|-w|-r] [-s list] [-m sys‐

$ COLUMNS=70 man apropos | head
APROPOS(1) Manual pager utils APROPOS(1)



NAME
 apropos - search the manual page names and descriptions

SYNOPSIS
 apropos [-dalv?V] [-e|-w|-r] [-s list] [-m system[,...]] [-M
 path] [-L locale] [-C file] keyword ...

With the version on Ubuntu 14.04, I need to write it:

COLUMNS=60 < /dev/null man apropos | head

There, man seems to disregard the COLUMNS environment variable if stdin is a terminal (it then queries the terminal device for the terminal width).

You can also try:

s=$(stty -g); stty cols 60; man apropos | head; stty "$s"

Which with zsh you can shorten to:

STTY='cols 60' man apropos | head

You could do it by invoking groff by hand as:

gzip -dcf "$(man -w apropos)" |
 groff -ekpstR -mtty-char -mandoc -Tutf8 -rLL=60n |
 col -bpx

Your can't find character with input code errors were because you used -Tascii instead of -Tutf8 and didn't use -k to pre-process the files with preconv.

You can use the fmt command, which as far as I know is present in any Linux distribution.

man apropos | fmt -w 70 

will wrap up lines at 70 characters.

You can use fold

man cp | fold -w 20

will fold after each 20 characters(!). Note that this will cut words in two as the only option is "fold every 20 characters"

taking care of this, you might use sed as follows (with dynamic line length)

man cp | sed 's/.20 /&n/g'

will add a newline after 20 random characters followed by a space (i.e. new word). So lines might be longer than 20 characters (match is 20 characters then a space so a 26-character word would result in a 26-character line)

For omitting the last space in the sed command:

sed 's/(.20) /1n/g'