Create man pages with gem help

man-gem.zsh

#!/bin/zsh
# Copyright (C) 2016  Ulysse Buonomo <[email protected]>
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

previous_working_directory=$PWD
root_dir=$(mktemp --directory /tmp/manthat.XXX)
cd $root_dir

# This function permit to clean all files until they are moved to
# /usr/local/man/man1, then the user shouldn’t hit ctrl-c
clean_temp() {
  echo "Cleaning $root_dir.."
  cd $previous_working_directory
  rm -rf $root_dir
}
# It should only trap 130, but ctrl-c seems to trigger a 2 code on my shell
trap 'clean_temp;exit 130' 2

# Change those two variable and the script will create man pages for any script
# that works the same way (git / bower / npm / mvn / ...)
main_command=gem
list=(build
      cert
      check
      cleanup
      contents
      dependency
      environment
      fetch
      generate_index
      help
      install
      list
      lock
      mirror
      open
      outdated
      owner
      pristine
      push
      query
      rdoc
      search
      server
      sources
      specification
      stale
      uninstall
      unpack
      update
      which
      yank)

for i in $list; do
  echo "Processing man page for \`$main_command $i\`.."
  help2man --no-discard-stderr "$main_command $i" > $main_command-$i.1
done

gzip *
mv -f * /usr/local/man/man1/
mandb

clean_temp()