install-dotfiles

#!/bin/bash
#
# install-dotfiles
#
# Installs symlinks to dotfiles in this repo into current user's $HOME dir.
#
# Blows away existing dotfiles, if they're currently symlinks. Does not check to see
# if those symlinks are pointing to what looks like this dotfiles repo or a variant
# of it, so be careful.

set -o errexit
set -o nounset
set -o pipefail
if [[ "${TRACE-0}" == "1" ]]; then set -o xtrace; fi

PROGRAM_NAME="$(basename $0)"

function usage() {
  cat <<EOF
$PROGRAM_NAME - install dotfile symlinks to the repo this script is in

Usage:
  $PROGRAM_NAME [-x] [-v]
  $PROGRAM_NAME -h

Options:
    -h    display help
    -v    verbose output
    -x    trace program execution
EOF
}

VERBOSE=0
OPT_TRACE=0
while getopts vkxh opt; do
  case $opt in
    v)
      VERBOSE=1
      ;;
    x)
      OPT_TRACE=1
      ;;
    h)
      usage
      exit 0
      ;;
    \?)
      echo >&2 "See '$PROGRAM_NAME -h' for usage"
      exit 1
      ;;
  esac
done


function v_echo() {
  if [[ $VERBOSE == 1 ]]; then
  	echo "$@"
  fi
}

function symlink() {
  local source="$1"
  local target="$2"
  if [[ -L "$target" ]]; then
    local current_source=$(readlink "$target")
    if [[ "$current_source" == "$source" ]]; then
      v_echo "Symlink '$target' is already set up"
  	  return
  	fi
  elif [[ -d "$target" && ! -L "$target" ]]; then
  	echo >&2 "ERROR: '$target' is a non-symlink directory"
  	exit 1
  elif [[ -f "$target" ]]; then
    echo "SKIPPED: File '$target' is a regular file"
    return
  fi
  ln -sfn "$source" "$target"
  printf '%-18s -> %s\n' "$target" "$source"
  CHANGED=1
}

function detect_os_type() {
  # Post: $OSNAME is set, or script has exited with an error status
  uname=$(uname)
  case $uname in
  	Darwin)
      if which sw_vers &>/dev/null && [[ $(sw_vers -productName) == "Mac OS X" ]]; then
      	OSNAME=macos
      else
      	OSNAME=darwin
      fi
      ;;
    *)
      OSNAME="$uname"
      ;;
  esac
}

function main() {

sourcedir=$(dirname "$0")
dotfiles_repo_dir="$sourcedir"
dotdir=$(cd $sourcedir/dotfiles; pwd)
todir=$HOME

detect_os_type

(
  CHANGED=0
  cd $todir

  # These files have their names munged to add a leading dot and strip extension.
  # Makes it easier to work with them in shell and editors.
  if [[ -e "$dotdir/$OSNAME" ]]; then
    dotfiles=( $( (ls $dotdir/generic; ls $dotdir/$OSNAME) | sort | uniq ) )
  else
    dotfiles=($(ls $dotdir/generic))
  fi
  for file in "${dotfiles[@]}"; do
    tofile=".${file%\.sh}"
    if [[ -e "$dotdir/$OSNAME/$file" ]]; then
      fromfile="$dotdir/$OSNAME/$file"
    else
      fromfile="$dotdir/generic/$file"
    fi
    symlink "$fromfile" "$tofile"
  done

  CHANGED=0
  symlink "${dotfiles_repo_dir}/bin" "bin"
  if [[ $CHANGED == 1 ]]; then
    echo "Linked the ~/bin directory. Don't forget to add it to your \$PATH."
  fi
)

echo "Dotfiles are now linked to $dotdir."

}


main
exit 0