Script for linking dotfiles using stow(8)

link.sh

#!/bin/sh
set -eu

print_help ()
{
  printf "Link dot files\n"
  printf "Usage: link.sh [--dry-run]\n"
}

if echo " $* " | grep -E ' (-h|--help) '
then
  print_help
  exit 0
fi

DRY_RUN=
if echo " $* " | grep -E ' (-n|--dry-run) '
then
  DRY_RUN=1
fi

MKDIR='mkdir -vp'
STOW='stow -v'
if [ -n "$DRY_RUN" ]
then
  MKDIR="echo $MKDIR"
  STOW="$STOW --no -v"
fi

if ! command -v stow >/dev/null 2>&1
then
  echo 'ERROR: You need to install stow(8).'
  exit 69
fi

cd "$( dirname "$0" )"
echo "Linking from $PWD to $HOME"

# We want to make sure that we'll link some directories as a whole,
# instead of their contents to make sure that if we add files there,
# they will be synced up
for dir in .vim .config/git .bash local/bin local/etc
do
  if [ -d "$HOME/$dir" ] && ! [ -L "$HOME/$dir" ]
  then
    echo "$dir should not exist"
    exit 1
  fi
done

# Similarly, we _do not_ want that to some files -- files created
# locally should not be synced, so we ensure that directories exist.
# Mark those files by putting a LEAF_DIR empty file in them
# shellcheck disable=SC2156
find . -name LEAF_DIR -exec sh -c "$MKDIR \$( dirname \"$HOME/{}\" )" \;

# A more elegant way might be to have multiple packages in this
# repository and only stow things that you need on a given machine, but
# that's too much effort, so we'll just keep everything in one bag.

package="$( basename "$PWD" )"
cd ..

$STOW "$package" --target="$HOME" \
  --ignore="LEAF_DIR" \
  --ignore="\.sync" \
  --ignore="\.gitignore" \
  --ignore="\.DS_Store" \
  --ignore="\.swp" \
  --ignore="pack.sh" \
  --ignore="link.sh"

# Running stow will fail if some of the files already exist. Usually the
# solution is to remove them from the machine before calling this
# script, but for some (currently bash config files) we want to keep
# main files not synced, so we instead link *.common file and source
# them in local ones.
# But we want to keep number of those files to minimum.

ensure_line ()
{
  target="$1"
  line="$2"
  if ! [ -e "$target" ] || ! grep -q "$line" "$target"
  then
    if [ -n "$DRY_RUN" ]
    then
      echo echo "$line" \>\> "$target"
    else
      echo "$line" >> "$target"
    fi
  fi
}

ensure_line "$HOME/.bashrc" 'source ~/.bashrc.common'
ensure_line "$HOME/.bash_profile" 'source ~/.bash_profile.common'