Script to check if it's worth it to compress man pages

manpage-compression-worth-it.sh

#! /bin/sh

# https://paludis.exherbo.org/faq/misfunctionality.html#wgetresume
# true<<TIL => shellcheck usefully complains...
til() { : ; }
til<<TIL
No Automatic Documentation Compression
Non-Problem: Paludis doesn't compress documentation or man pages with gzip/bzip/whatever.

Rationale: The space savings on an average system are very small, to non-existent for most filesystems. Most documentation and man pages are only about one block in size, so compression won't gain you anything except for wasted CPU cycles.
TIL

# Absolutely true on my void install! (2K uncompressed)
# Instead on debian I get instead compressed=>2042, uncompressed median 4810 bytes!
# (assuming filesystems use blocks >= 4KB)

shellcheck "$0"

# Disable warnings about use of egrep and fgrep; also $(($N + 1))
# shellcheck disable=SC2196,SC2197,SC2004
# The rationale is:
#	$ a='1+1'
#	$ echo $(($a * 5))    # becomes 1+1*5
#	6
#	$ echo $((a * 5))     # evaluates as (1+1)*5
# The colon (':') is to put unknown options in $OPTARG.

# TODO does anyone use bzip2, xz, ...?
measureCompressedManpages() {
        unset -f useraw cook
        eval 'useraw() { iscompressed "$1" ; }'
        eval 'cook() { cat "$1" | gzip ; }'
}
measureVanillaManpages() {
        unset -f useraw cook
        eval 'useraw() { if iscompressed "$1" ; then false; else true; fi ; }'
        eval 'cook() { cat "$1" | gzip -d || ls -ld "$1" ; }'
}
measureVanillaManpages

# Use _getopts_, "getopt" is deprecated (it has long options & shuffling)
while getopts ":cd" Option ; do
        case $Option in
                (c) measureCompressedManpages ;;
                (d) measureVanillaManpages ;;
                (*) echo "unknown option $OPTARG" >&2; exit 100;;
        esac
done
shift $((OPTIND - 1))

iscompressed() {
        case "$1" in
                (*.gz|*.bz2) true ;;
                (*) false ;;
        esac
}

if test -t 1 ; then
        echo >&2 "Usage: $0 [-dc] [DIR...] | ministat -A"
        exit 100
fi

test $# -gt 0 || set -- /usr/man /usr/share/man /usr/local/share/man

for dir in "$@" ; do
        cd "$dir" || continue
        for i in m*/*.* ; do
                test -e "$i" || continue # broken symlinks happen
                test -d "$i" && continue # internationalization
                if useraw "$i" ; then
                        wc -c <"$i"
                else
                        cook "$i" | wc -c
                fi
        done
done