Centre align a Linux man page

As a Linux user, I often have to refer to the manual pages to learn things. Now I don’t have a huge monitor as many people have these days, but I have a 24" screen and it’s not the best experience when reading a man page.

Today when I opened a man page, I found it so unreadable that I did a quick web search for “man page width” and found that the variable MANWIDTH controls how broad the output should be. That led me to search for “man page margin” and then “man page centre justified” which landed me on this answer.

Using this info, I first created a ~/bin/olivetti file that’s exactly as mentioned in that answer with the only exception that I have used WIDTH=$MANWIDTH instead of WIDTH=100:

$ cat ~/bin/olivetti
#!/bin/sh
# Define desired width of the text.
WIDTH=$MANWIDTH
# Evaluate left indentation based on terminal width.
INDENT=$(( ( $(tput cols) - $WIDTH ) / 2 ))
# Make line of that amount of spaces.
INDENT_LINE=$( printf %${INDENT}s )
# Put it on the beginning of each line of the input file.
sed "s/^/${INDENT_LINE}/" -

And then put a simple function in ~/.zshrc file that looks like:

function m {
    man $1 | olivetti | less
}

Now, to open a center justified man page that’s only 100 columns wide, I run m followed by whatever it is that I’m looking up, e.g., m bootup to read the Linux bootup process.