Print a random manpage. You can specify a section to pick the manpage from.

daily-man.sh

#!/bin/bash

# Print a random manpage.
# You can specify a section to pick manpage from.

NROFF_DIR=/usr/share/man/man
PAGE_EXT=gz
MANPAGES_LIST=/tmp/manpages
section="*"

# Get manpage section wanted
if [ $# -eq 1 ]
then 
        if [ "$1" == "-h" ] || [ "$1" == "--help" ]
        then
                echo "usage: $0 [section]"
                echo ""
                echo "section: 0-9, show only a manpage of this section"
                exit 0
        elif [ "$1" -ge 0 ] && [ "$1" -le 9 ]
        then
                section="$1"
        fi
fi

# List all manpages (of specified section)
find "${NROFF_DIR}"${section} -name "*${PAGE_EXT}" 1> ${MANPAGES_LIST}

lines=$(wc -l ${MANPAGES_LIST} | cut -d ' ' -f 1)
if [ "${lines}" -eq 0 ]
then
        echo "No manpage in this section..." >&2
        exit 1
fi

# Pick a random manpage
page=$(sed -n "$((RANDOM % lines))p" ${MANPAGES_LIST})

/bin/man "${page}"